[dmurray]

There are also explicit laws forbidding telling your customers of your suspicions ("tipping off" in the context of money laundering).

Of course, this doesn't mean your customer service agents should never be helpful and forthcoming, but it's easier and less risky to tell them to say nothing and burn the odd legit customer, rather than risk being on the wrong side of AML legislation.

[raincom]

If a mandatory reporter files a SAR, they are forbidden to share that info with customers. This doesn’t apply so much with payment processors. Stripe and others just don’t want to share their heuristics, because carders can thwart these heuristics. That’s more reasonable suspicion than some laws.