So i was browsing the Dungeon Defenders official forums and apparently they are working on VAC securing the game wich will ban everyone that uses a trainer.. just thought i'd let you guys know. Kinda sux that they take it to such an "extreme" i mean it's not a competative game, but oh well.
Actually, if you read more carefully you would see that VAC security only applies to the online 'ranked' play. As 'ranked' play game data is stored on the cloud and not locally, the trainer won't even work on it anyways.
The 'open' play is okay to use the trainer on and won't result in a steam ban as it is meant for modding etc anyways.