Mike:
Response to Q1: Based on TDA Rule 29, I would hold the player to the 17,200 verbal declaration. That said, if the player had stated "All-in for 17,200", then I would hold her to the "All-In".
Your description of the situation said, "She is clearly making an effort to count all her chips."
Response to Q2: If this is an "All-In", based on your description of the situation, in which you said "Player A has about 10 BB's in chips remaining in stack.", which would be about 20K. The difference is right around 15%, so I would hold the player to the full amount.
Response to Q3: If you are at the WSOP, under Rule 91 (I think that is what it is now) Player B is responsible for ascertaining the correct amount of the action by Player A. Once Player B says, "Okay, I'll Call", he is bound to the amount of Player A's action regardless of the amount.
If there was a "Major Undercount" of lets say 8K, then player A had to have considerably more than 10BB's to start the hand. An undercount of 8K would be almost 50% of the stated amount, so depending upon other factors (remember you said she was "...making an effort to count her chips.", I may very well release Player B or I may hold Player B to the All-in. I think a lot depends upon the experience level of both players. If A is a "newbie" for example and B is not, I again may hold B. If reversed, A is experienced and B is a newbie, I may release B. If both are experienced, I may hold B again as I would if both were experienced but drunk.
