I'm going to mess with the elevator in Fort Zancudo. A few times when I ran in there, there were tons of guards inside trying to kill me, and then every other time, there were none unless I climbed to the minigun. Will post if I find anything.
Yeah, it's weird. One time I went in the base, I got no stars (I ordered a taxi and put my waypoint to the end of the bridge/entrance road, I skipped the drive and the taxi spawned inside the base.) and I went down to the elevator, the light was flashing but no siren. Then I went to the tower and the guards didn't attack me at all. It was very strange, then I hit one on my way out after getting the minigun and then they went beserk. I think it was a glitch.
When you used the taxi glitch to get inside the fort, was this in SP or online? It never has worked for me, I always get wanted stars.