Imagine the fun this is for casinos? It is quite common for casino customers to make a series of $1,000 buys as they play at high stakes tables. For their good patronage, the casino gets to report them as possible money launderers to the government.
The Casino wouldn't file a SAR on a high roller for activity that happens during the normal course of a game. In the situation you described they would file a CTR if he broke the $10,000 threshold.
These are the basic SAR requirements for a Casino:
The BSA regulations require a casino to file a Casino SAR (SARC) for any transaction conducted or attempted by, at, or through a casino, and involving or aggregating at least $5,000 in funds or other assets, that the casino knows, suspects, or has reason to suspect:
• involves funds derived from illegal activity or is intended or conducted in order to hide or disguise funds or assets derived from illegal activity (money laundering);
• is designed to evade the reporting or recordkeeping requirements of the BSA (structuring);
• has no business or apparent lawful purpose or is not the sort in which the particular customer would normally be expected to engage, and the casino knows of no reasonable explanation for the transaction after examining the available facts; or
• involves use of the casino to facilitate criminal activity.
That said I can imagine it is a headache trying to distinguish customers acting in a suspicious manner versus customers who are just drunk and gambling.