Person won the collector's edition of Guns of Icarus from me when he already owns the basic edition

+1

Sometimes collector's/GOTY editions are bundled, but the DLCs themselves are not (separately bundled). However, as I recall, since the GOTY edition is added to the bundle list, the DLCs are as well.
End result, the DLCs become hard to get, especially with DLCs often not going heavily on sale on Steam.

So yes, some GA creators do allow entry for bonus content, for specific games, with that in mind.
(In this case, the collector's edition hasn't been bundled, afaik, so the entrant may have expected some GA creators to be agreeable to the matter; of course, if s/he didn't bother clarifying that with you beforehand, then that's on them.)

Past that, I'm totally with you, I can't stand when people enter- well, I saw a person once try to enter for a $2 DLC on a $50~ package. :/

But even past examples that extreme, and ignoring special circumstance games- if the retail price of the (content you don't own) is less than (the cost of the bundle), you probably shouldn't enter, out of respect of those that don't own the base game and the GA creator (and of just not being wasteful in general >.>) :/

Could you confirm it was the old winner? It's something, at least...
In my case, it's only a (pretty accurate) assumption, since the old winner is one of those so-called "leeches" who only take without giving back.

has this actually been confirmed.

Directly by staff, multiple times.
One of the examples they gave at one point is the Deponia Trilogy, which has exclusive features and you can't upgrade to.
Personally, I disagree heavily on that one, since none of the bonus features have any bearing on gameplay whatsoever...

But there are other games.. well, for example, Enhanced/Remastered Editions, the Metro Redux Editions, (presumably the Dead Island Definitive Editions), etc- They all don't count for rerolls since, despite technically being the same game, they've substantial content differences.

That all said, in each of those instances, they would be a different library entry- so as you suggested, that may be an actual requirement that they simply hadn't clarified in my encounters with the matter.

That aside, your specific example is, to the best of my knowledge, incorrect- you're not allowed to get the exact same game, even if the appids are different. The devs do consider different steam entries for the same exact game to be, well, the same exact game.
Likewise, I'm fairly certain they don't allow you to enter for different regional versions of the same game, even if they count as completely separate game versions.

Well, I'll poke this post toward staff, maybe they can give us a fresh clarification when they have a free moment. :)

a reroll is supported by the rules in your case, so don't pay attention to these comments. :3

you could even reroll someone that owns 1 game from a 50-games pack.