Previously, amx_addban allowed any user with ban access to ban any steamid, which could go around immunity. Obviously this was bad.
This can be solved by check, if banned SteamID has immunity or not (via users.ini)..
I still dont get the idea of stack last connections. If is set up to 10 connections for example, cheater join and play. Between calling admin more that 10 players left and join new (because cheater is reason for player leaves). Well, when admin goes to server to check out, and cheater leave, cheater not be in last 10 connections (if i understand it right).
Anyway, i teach every admin on my servers: When are you called to server because cheater (or have suspicious to cheat), the first thing after join (or suspicion) is amx_who
(against cheater lefts, and possibility to later unban), and then spectating, if someone cheats... Amx_who left detailed information about players in admins console, so where is a problem?