Profile Steam only for friends and winning games at SG

It's not against the rules of SG to have a private profile as long as you sync regularly.
People will be unable to check your status manually though and may as a result develop mistrust towards you. Since users have a lot of power on this site (most notably blacklisting), you could get suspected of things you may or may not do since they're not able to verify things with their own eyes.
SG will automatically manage which games you own and which groups you're in every time you sync, but everyone else will just have to assume that the information is correct/up to date.

some people dislike private profiles but it's not against the rules as dan mentioned.

if you win, expect the ga creator to ask you to set your profile to public so he can check it.

Thank you for answers. I have not found this place, is there a process as to SG insert information about the authors giveawy to invite me to friends on Steam if I win the game (and after verification that they removed me if she would like)?

First of all, why set it private?
Don't you love the feeling of people stalking you?