[Mr.Silence]

Judging from the logs, it looks like this person had attempted to change the value of sv_cheats on the server, which will trigger a ban from the plugin.

Please keep in mind that the smac_cvar plugin will lock your server's sv_cheats value to 0 and changing its value, even if it was done innocently or by an admin, will result in a ban. It is advised to either avoid using sv_cheats on a server using the smac_cvar plugin or, if you want to use sv_cheats on the server, you should remove/unload the plugin from the server when using sv_cheats.

If you trust this person and/or this person had admin on the server, then it might have been a false ban, just be sure to let them know not to use sv_cheats on the server next time.