"However, the filing of an SAR does not require the bank to cease doing business with the client in question." This feels broken. Was this intended to prevent competitors from falsely filing SARs against each other to freeze their business? What are the penalties for abusing this system?
A SAR just means activity is suspicious. That's it - a SAR is not by itself evidence of wrongdoing, just a report to take a deeper look. "Hey, this persons makes mostly foreign transactions with vague companies" is a SAR. That's not a crime, and it may not be criminal behavior - it's just an indicator that someone should look closer. Can you imagine if your bank closed your account and refused to do business with you…
Ugh. I'd pay more for a credit card which didn't block my own transactions. Using a US credit card abroad can be seriously frustrating.
The only thing worse than rapidly increasing airfares on small airlines with websites which barely work is when your credit card refuses to complete the transaction, requiring multiple international phone calls to resolve.