Tristan: Great question, and hopefully we can develop a greater consensus on this at Summit VI. I think the 2+2 thread summarizes the two basic interpretations:
Version 1. When player A says "raise", he's at least committed to a min raise. So if Player A min-raises, Player B must call the min-raise. If Player A raises any more than that, Player B has all options open.
Version 2. Player A says "raise" and Player B says "call". There is a unstated condition statement "I'm going to call whatever you raise", it's implied. Therefore under TDA Rule 51, the TD may hold Player B to calling any raise amount.
This is clearly a Rule 1 decision as it is so non-standard. Personally I hate the idea of a player getting to look at his opponent's cards and decide how much to raise him after he sees the hand, and KNOWING that whatever he raises, the guy must call... that's just gift upon gift. However, the opponent is 100% responsible for putting himself in the situation. Further there is zero doubt in my mind he would have called any bet, including all-in, and his gesture probably looked for all the world, turning up his cards, like he thought he was calling an all-in. ... and I also hate like *&^%$ denying Player A the opportunity to bust Player B which he almost certainly would do, if Player B hadn't made two mistakes.
At the end of the day, you have latitude to make the fairest ruling you can. IF the situation is 100% the fault of the caller / tabler then I'm really leaning towards holding him to call anything. If there were other causal factors then I might look at other remedies.