It should be perma IMHO as well.
I agree... However, it's a very sticky situation, when you need absolute proof a specific player was botting.
That is extremely hard to prove.
I was involved in a situation whereby we had a report of a player killing the same mobs in the same rotation and same locations, for hours every single day.
We monitored the account and then banned it. The player never returned our 'tells'.
His father then contacted us, and explained it was his son who had asbergers? or something like that, and that was what he did. Talked to no-one and killed mobs over and over again.
We had to re-instate the account and make an apology. That was in the 90s.. Imagine the law suit now?