Validation refers to the subgame security mechanism that restricts staff powers usage to selected players. This helps prevent an untrustworthy staff member from giving one of your staff passwords away, thus allowing anybody to have staff powers. Although an unauthorized player will still technically be logged in as staff, subgame will reject (and display a warning about) any attempted commands usage.
To turn on validation, configure the following booleans in server.ini:
[Validation] CheckMod=1 CheckSMod=1 CheckSysop=1
To authorize a player as a Sysop, SMod, or Moderator, just add the name to the lists in (newline-separated) sysop.txt, smod.txt, or moderate.txt, respectively. Afterwards, you may also restrict his or her powers to certain arenas with the syntax +playername:arenaname. Leave arenaname blank to allow all private arenas, or set to '@' to allow all public arenas. You may also have mutliple restriction lines to specify multiple allowed arenas. Note that you must first add the playername without restrictions and then you may restrict the powers on the following lines. Example:
Mine GO BOOM +Mine GO BOOM:mgbarena