I have spotted and loaded at plenty of meets and caught 500+ lbs on a missed bench. One reason is the level of seriousness we instill in all of our lifters.
Also, as a coach/lifter I am constantly watching the spotters. If I feel at any time that my, or any lifters may be in danger, I bring it up to the judges and in a few cases I have gotten spotters removed from the platform.
At Collegiates in Denver in '08, I was coaching with LSU, and we had to pull a spotter off the platform because he was undersized and didnt know what he was doing. I then spotted the rest of the squats for that flight.