Why can we shoot a guard through a glass door window without anyone hearing the glass break? Why can't the guards see through the bulletproof booth windows when we can?
Why does the alarm not trigger when entering the casino/vault after bumping off most of the upstairs staff in the lobby? Where do all those bodies magically disappear to?
Metal Gear Solid or Splinter Cell this isn't. The stealth approach was already laughably inconsistent and poorly designed all the stealth approaches including the Big Con ones are far more taxing for no benefit. 2 new guards spawning only after leaving the lower floor is a cheap trick. In my next run I was planning to execute everyone downstairs and see if that made any difference. I usually bump off the guy in the booth and the roaming guard leaving 2-3 behind near the lift then head up the stairs. I'm pretty sure the guy at the desk needs to go as his vision cone covers the doors. I've noticed this happening myself on the last few runs.