When the couple are on the boat, the gentleman is sipping his margarita and the level of his drink is down to the top of the glass stem. When he sets his glass down to go for a swim, it is now half full.
Right after Kelsey shoots Nina Stahl, and the view changes to the helicopter out the window, you can see a parachute in the top left of the screen.
In the final scene when Daryl Hannah and Doug Savant are in the aerial tram, they begin hugging and in the reflection of the window, you can see clearly the camera man's lower half ... complete with red Hawaiian shorts and scrawny chicken legs.
When Agent McGregor answers the knocks on the suite door with her boyfriend on the bed, she does not use the peephole in the door before opening it. No trained security detail, much less the Secret Service, would do that.
When the agent shoots the unarmed man in the woods in the chest after shooting the other agent he plants the gun in him but fails to fire it. So no gunfire residue would be found on the man.