Kicks and Bans are two different critters :)
A server can be setup to "kick" for a variety of things....and those things could all be non-bannable offenses. PBBans uses the violations identified by PunkBuster as the basis for bans. They range from Aimbot, Wallhack, Multihack, PB Hack, etc. You may also notice a few bans appear that come from CVAR and MD5Tool scans. These scans take PunkBuster one step further and bans people using or possessing known cheats on their computers.