Nice SG feature I just realized. :)

yup, automatically forces you out of GA's for anything you own, its half of why I sync when I activate anything, I can never remember if I am in any GA's for it.

other half is hiding them automatically.

Just from 5 years ago. ^^
https://www.steamgifts.com/discussion/L5URh/giveaway-entry-changes

Thanks for the confirmation and link, folks. :)

SG won't let you enter a GA for a game you already own, but if you recently activated a game on Steam and are already entered for GAs for that game, SG won't know you own it until the next time it does a sync. You can manually sync if you activate games or add games to your wishlist and use that feature here, but you don't otherwise need to do them because SG will automatically do a sync when you open the site if it has been at least 72 hours since the last sync.