Corbin seat? The only thing holding on to the bike is a little Phillips head screw. My only idea so far to use a less common screw or bolt, i.e. Torx so it will be more difficult for the would be thief. Someone's gotta have experience here.
If you are that worried about it, take the seat with you when you park it. One screw, pop it of and you have piece of mind. Personally I think they will steal the whole bike before just the seat
My seat is held on with Velcro and nobody has stolen it for the ten years I have owned it. I wouldn't sweat the seat, I'd be more worried about someone stealing the whole bike.
Your over thinking this...............no one wants to take your seat........relax. My Danny Gray is held on with a suction cup. They might take the bike,but not the seat alone