Are banks required to cash U.S. Treasury checks for non customers?

No. There is no such requirement.

Unfortunately it depends on your location. In MA (if you are a MA state chartered bank) you are required to cash US Treasury SS and SSI checks for non-customers if they are retirees or pensioneers, the check is for less than $2,500 and the person can be positively identified. There are other defining factors but we are required to cash them.

I stand corrected. Sorry, I never thought of state laws since Kentucky doesn't require this.

You are very fortunate that KY doesn't require this. It's rather irritating and frustrating to deal with. I would rather not have to deal with it at all since staff are not the best about "positively" identifying people. Too much room for fraud in my opinion.

Where would we usually find such restrictions? I've check the NM Statutes and the Administrative Code and don't see any obvious rules regarding cashing of Treasury checks.

MA ruling is listed in the Massachusetts General Laws. Not sure what this might be called in NM or even if you have this type of restriction or not.

You might also post in the state specific forum for the experts to reply.

It's rare, very rare. The first phone call I would make to confirm any such requirement would be to the state department of banking in your state. It's a pretty sure thing that they would be aware of it as complaints about noncompliance would likely be routed to them or the OAG's office.

It figures I am in one of the "rare" states, Ken.