There are two problems you have to address when looking at this issue: 1) if you disclose non-public information to law enforcement and that leads to a prosecution there's a good chance that the evidence and anything it lead to will be thrown out of court. 2) your privacy policy probably says you won't disclose non-public information to a non-affiliated 3rd party . . . and law enforcement is a non-affiliated 3rd party.
But here's what you can do. If law enforcement starts sniffing around one of your accounts, look for any excuse to file a SAR. The SAR is you, as a private citizen, saying there's something odd here. Law enforcement is always free to act on tips received from the public and your privacy policy surely states that you will disclose things "required by law" and the law requires you to file SAR's.
Just make sure you can justify any SAR that you file.
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If you approach life with pure logic you can avoid almost all of the fun.