I do in fact think signs work! Not for all of course BUT I think they help greatly.
It makes a lot of people nervous, especially when they could tresspass anywhere- they look at the non-posted property that they know isn't cared about or monitored BEFORE they want to take the risk of going on the one that's freshly posted and they think it's monitord (trail-cams or whatever). *I wouldn't go overboard with these huge reward signs and huge Surveillance camera signs, I see them near my land and i think it's just a major step further than needed (regular signs make the same point) that just makes you look like a jack-a$$. Make your point tastefully, IMO.
I had 3 years on an 80 with NO SIGNS, every year- groups of guys. I posted it, let everyone knew I was respectfully getting sick of it AND I let people know I used trail-cams for deer (which is seriously my main reason for using them) and I'd say tresspassing went down by 90%.
Many guys out there aren't looking for the super-crafty way to sneak on, there's sure a handfull that are BUT I'd say 70% are not. Who wants to hunt when you're all nervous and doing what is so OBVIOUSLY not cool?!?! I'd say 70% don't do that. Post, talk around and watch it close and you'll REDUCE problems. Thinking and trying to stop 100% of people will just stress you out- DON'T WORRY BOUT IT past doing the above.
*I also set many Booby-Traps, tigers in pits, nets that pull you up in the trees, swinging swords, trip wires with grenades and shotguns with trip wires- Unintendend consequence is I killed all my deer as well /forum/images/%%GRAEMLIN_URL%%/frown.gif