Argus, thanks for clarifying the situation. I note this though:

[ QUOTE ]
Player A did not check. He was not planning on checking. He was going to bet $100 and Player B was going to call and just loose $100.

[/ QUOTE ]

Why would you want to "just lose $100"? Player B thought he had the best hand and called the psuedo check-raise.

One way to look at this is that it could have saved player B $150, I am sure the floor would allow him to take back the $50 and simply fold. You are usually behind when you get check-raised, especially in a show-down. However, it is hard to lay down a flush.