Visible crew/equipment: When Mason is fighting the guy whose legs are on fire, watch Mason's hair. It's completely different from Sean Connery's. It's thicker and there's more of it, and at one point you can see the stunt guy's face.
Visible crew/equipment: When Sean Connery is fighting the guy whose legs are on fire, watch Sean's stunt double. There's a rope and a metal safety harness holding him steady.
Visible crew/equipment: During the Humvee chase, right after the FBI car is on its wheels, you see someone wearing a helmet come out the car. There were no police bikes in the chase so that means it was a stuntman who got out.
Visible crew/equipment: Right near the very end where you have the overhead shot of the bombs hitting the back of the island you see Stanley Goodspeed being thrown through the air by the force of the explosion, and into the water. As he is flying through the air you can see the wires he is attached to, to make him fly.
Visible crew/equipment: In the interrogation room, it shows the mirror reflecting Mason, Goodspeed and the other guy. Look carefully: for a split second you can see a shine of a watch, then an arm, of the cameraman.
Chosen answer: Alcatraz is small enough and out in the middle of the bay that any lookout in a high point could see and hear a chopper, no matter where it approached from. The idea of the decoys was to split any enemy fire received. The whole insertion of SEALS was absurd, in a real situation like that, the SEALS would have been inserted by submarine or used dive motors to pull themselves to the island.
Grumpy Scot