*sigh*... I posted some simple code a while back that gives a user an error page stating they are banned for X time, etc... (It doesn't give a reason because I didn't want to start modifying a lot of pages)...
Take a look, maybe this will tide you over until it's integraded into vB3:
https://vborg.vbsupport.ru/showthread.php?t=62313
I think that is one of the worst oversights on the part of the vB3 team... When you ban a person they just get a generic no permissions page, so I was getting flooded with emails asking wtf was going on... a specific ban page is almost a necessity...