Staff (or more specifically Globals/admins) can already give the reason for a ban and also its duration, but it's clunky and time consuming to do, especially when some people are reporting dozens of copy and pasters at a time. There's a ban button that automatically bans the user and their IP so that is usually used for copy and pasters to save time. I have requested an additional ban button for plagiarisers that automatically states the reason for the ban and that's it's permanent so this confusion will be cleared up, but whether we get it or not is doubtful.