In a simple words, there are high chances that ban evasion is related to a scam attempt. Ban evasion, in more than several occasions than we cared to admit, happen because someone tries to cheat the system. Either they violated forum rules, bounty abusing, or they tried to scam someone, and the likes of it; be it a temporary ban or permaban. An honest person would wait for the tempo ban to over or plead over the meta section [this is allowed]. But a cheater or a known scammer, whose got their account banned for that reason, fully know that there is no way to reinstate their account will choose to create a new account --thus, ban evasion-- to continue their agenda. Should this not be tagged?
We should separating between ban evader and scammer or abuser.
Not all ban evader are scammer or abuser because he was banned because of committing plagiarism, so he only deserve to get a neutral feedback, it's different if the ban evader was an abuser or scammer.
Now what if the ban evader which never scam or abuse created a new alt account in order to milking the forum by joining a signature campaign? this one is tricky. Some people will say let alone his business because he's not high risk of losing money. Some people will say he's a dishonest person and deserve to get negative feedback.
I am seriously curious and interested about this. I gave a quick stroll at other threads and saw that you're not the only one standing to this opinion. I am somewhat agreed that it's mod's job to ban them, but shouldn't --or couldn't-- the DT leave a tag on that user before mods can take action and nuked the account to prevent the account from doing further harm to the forum?
I want to clarify if I'm not supporting ban evader, but I don't know why you can think the account will cause a further harm to the forum. It's more like your own assumption rather than being objective about what he had done in this forum.