The channels later returned to monetization when they started adding “fan trailer,” “parody” and “concept trailer” to their video titles. But those caveats disappeared In recent months, prompting concern in the fan-made trailer community.

YouTube’s position is that the channels’ decision to revert to their previous behavior violated its spam and misleading-metadata policies. This resulted in their termination.

It sounds like they only banned them for not having a disclaimer that it isn’t a real trailer, so unless that deters people from clicking on them, I assume others will do the same thing just making sure to disclose.