Are any of these grounds for a re-roll?

I meant if they enter one of your other giveaways than the one that was leaked.

Isn't it more like:

report him for inappropriate behavior -> he get suspended -> you can ask for reroll because hes now suspended?

Yes. If that happened to me I'd wait the full 7 days to see if they actually go through with any lame threats, then report and ask for a reroll.

Thanks! Then I know I'll at least have some protection against the really rude people out there.

I'm not sure if I understood the second one correctly. So if I were o make a train with SGTools with a check on the first giveaway, only that one would be grounds for re-roll if it gets leaked? I want to make some giveaways in the near future and it would be a pain in the ass to put SGTools checks in every single giveaway, for me and the entrants.

If it's a train behind sgtools, all giveaways in the train should be protected and eligible for reroll. I'm not entirely sure what you mean by what you said.

I have been granted a reroll due to a winner being really annoying towards me, but the guy did not get any kind of punishment/suspension. Shouldn't there at least be a one day break for "Inappropriate behaviour"?

You should only enter to win giveaways for yourself, and if you win a game, it must be activated and redeemed to the Steam account used during registration. If a friend is interesting in joining giveaways, they'll need to register for their own account.

What are levels, and how can I increase my level?

Levels represent a user's contributions to the community. When a user creates a giveaway that's received by the winner, their level increases in value, allowing them access to additional giveaways as a reward. Levels range from 0 - 10, with level 0 being the default after registration, and level 10 being the highest level attainable. If you mouseover your level in the navigation bar, or the level on profiles, you'll see a tooltip with the level rounded to 2 decimal places, giving you a better idea of small increments in level, and when you're about to level up.
Levels increase almost exponentially, meaning each level requires double the contributions of the previous level. For example, level 4 would require double the contributions of level 3, and level 3 would require double the contributions of level 2.
How much a giveaway increases your level is based on the gifts price, so a $20 game would add twice as much value to your level as a $10 game. There are three other factors that may influence the value of a gift...
After you give away a game 5 times (whether in the same giveaway, or in multiple giveaways), it will begin decreasing in value. The value is decreased by 10% for each additional copy. This means if you decide to give away 8 copies of a $10 game, it would add $74.39 (10 + 10 + 10 + 10 + 10 + 9 + 8.10 + 7.29) in value towards your level. This has little effect on the majority of users, but prevents individuals from receiving a high level from gifting a large number of promotional gifts, games obtained through pricing errors, or keys from contacting game developers.
If a giveaway is invite only, or for a whitelist or Steam group, it will only add value towards your level if it receives 5 or more entries. This is in place to prevent small groups of friends from attempting to cheat the contributor system, and to encourage users to expand the reach of their giveaways. The whitelist feature offers an easy way to target a larger audience, and you can combine it with small Steam groups to receive a greater number of giveaway entries if needed.
Giveaways for bundle games created after the bundle date will always receive 15% of their value. For example, if you gift 2 copies of a $20 bundle game, you would receive $6 (3 + 3) in value towards your level. Keep in mind that changes to the list of bundle games will apply retroactively, so if a bundle begins today, attempting to gift the game before it's added to the list will offer no advantage. Games may also be added to the bundle list if they're available for free during a promotion, or if they're highly discounted in a sale.

Edit: I couldn't do formatting but FAQ has your answers.

the first two violate the TOS and a grounds for a ban. the last one can be found out by searching the related topic on the forum

-Is there any rule against the winner not activating the key on his/her own steam account? Or is it just unethical?

It's against the rules to not activate it on the steam account you registered on. It's in the faq

-Is there any rule against the winner creating a new giveaway, with the same key he/she has just received?

Yes. All games won must be activated on your steam account, so you can't give them away.

-Is there a certain value($) for gaining levels?

Yes. See this thread

For the first question: You should only enter to win giveaways for yourself, and if you win a game, it must be activated and redeemed to the Steam account used during registration. If a friend is interesting in joining giveaways, they'll need to register for their own account. (From FAQ)

So obviously regifting is also against rules. And yeah, there is, though it's in real CV (games considered bundled have lower CV).

Oh, yes. For some reason, couldn't see below "How does a blacklist work?" in FAQ. Thank you all for your answers.

A couple of days ago there was a person here that was doing something called regifting (I think that is what they called it). Basically they won a game in a giveaway and then tried to do a giveaway on the same game. There were a lot of posts saying that the person should cancel the giveaway, but I'm not sure if they ever did.

Even though I really wanted the game and could have entered the giveaway, I chose not to, as someone else could have won the original giveaway had the original winner not really wanted it in the first place.

I don't get why he would get so furious, but you shouldn't contact the creator. You should leave it to him (I think it might even be in the rules). Still, no reason to get that mad.

I had it happen to me once that someone added me immediatly after the GA ended (I didn't even know who the winner was yet) and directly told me to just give him the key because he won. I just told him to be patient and that I would send it when I wanted. Deleted him as a friend and waited to send to key for two days.

It is kind of annoying for the creator to get added so soon. I wouldn't mind it too much, if the person at least was polite, but some do mind it (unfortunatly).

From FAQ: "Please remain patient, and do not contact the giveaway creator during this time." So... Sure, he probably overreacted, but it's still against rules.

Well... Unless you know the GA creator and you can allow to behave this way after winning or you are very obvious with that, you can't expect people to understand your sarcasm (especially if it sounds really rude and ungrateful).

Never use sarcasm when on a computer. From typed stuff you can't see if it's sarcasm and in most cases it will be picked up seriously. If you report them, they can't defend themselfes with "it was just sarcasm."

Of course. What does he know about this...

Who's this Tempete person? Must be some wannabe support