JIM G,

Any time a table player gets close to losing $10,001, the action is stopped and he must produce 2 forms of ID before he goes over $10,001. The floor man must keep a record of all buys until he gets to this figure. There is a big fine for not doing this and another big fine for letting a player go over $10,001 without telling him 1st.

A player cashing out 10,001 must also produce ID. In theroy a player can lose or win $10,000 every 24 hours without showing ID, $10,001 is the threshold for reporting.
The form is called a CTR and casino people are trained on filling it out.
Not filling it out is immediate termination, in most cases.