[Rottersod]

I'm going to have to go with he should have been required to put in the entire bet. In LA we see a different scenario all the time: raise preflop and small blind puts in chips to complete what he thought was an unraised pot but when the dealer informs him that it was raised he is allowed to take his chips back and muck. This is fine but your scenario was different. He had already called the blinds so he knew that there was a raise that he was calling - he just lost track of how much it was. He did throw chips in and since they were all going to the raise he should be responsible for competing it. An expensive lesson yes, but maybe a lesson that will stick with him. IMO, the floor handled this poorly, as you alluded to the fact that at a different table it may very well have gotten him in some hot water. Consistency should be the mantra.