Why isn't a tag appropriate in your opinion? Have seen other tags before for the sole reason of a behavior + email change.
He will be banned due to his spam behavior. About sold/hacked account, there is no proof for this, it's just your suspicion, DTs cannot abuse trust system. Please understand them.
I believe you have no clue.
Your post has exactly 0 added value.
If you want to make a valuable post, please explain HOW this is an abuse of the trust system.
If a DT sees this, analyzes it, and this makes him distrust the user, tagging him is NO abuse. Also the tagged user could really easily prove the account is his to remove the tag.
He'd just have to provide a signed message from one of the adresses used and quoted in his post history.
Also since he is bumping only 1/day or less various local threads, I doubt he will be banned for spam.
Goodbye