The reason the trainers are wrongly flagged is because of a few bytes difference from known virus code strings, the heuristic system kicks in just in case the file is a variant of a known virus.
Now if a AV doesn't do this at any time you have it, whether it is trainers, etc then be worried then.
* Updated game trainers and cheats daily
* Get notified when new cheats are added
* Request which games get new trainers
* Priority support with any problem