Not activated Gifts on account Zampone
Before calling out / reporting someone, please manually check the results
Also check if user profile is not private (If it's private ask a Support Member to check it for you).
As you'll read on each section, steam API has some bugs that may result in an inaccurate non-activated detection
Games wins not activated
There are some rare cases where some base steam games are not recognized as owned. This site uses a whitelist for not showing those games, if you find one please report it in the Official forum thread.
Also games that are "Deluxe Edition", "GOTY" or in general a bundle of game+dlcs in a single app (not in a steam package) are usually a false positives.
Games that are well-known false positives and have been whitelisted in the tool
All of these are most probably activated, you just have to check if the user owns the base game for entries that are goty, deluxe, complete, etc...
Show me those Whitelisted games/DLCs!
DLCs Wins that appears as not activated
Steam API has problems identifying some owned DLCs, so the following ones are probably activated!
Show me those DLCs!