You're repeating if(CheckCommandAccess(client, "sm_addban", ADMFLAG_RCON, true) && GetConVarInt(AdminControlType) == 1) a lot. You might want to put it into a function.
and i just noticed, admin or not admin. if you have access to the command or not. = warnings.
regular ppl who is not admin but just type !slay gets their ass owned by this plugin. and admins can avoid this using admin menu.
right now i saw this as a very fun plugin so i could just troll my admins. now i notice it was a waste of time after some normal player on my server gets rekt by this shit. adding this just makes regular players leave the server.