When it comes to permits to mail at a presort, bulk or discount rate, those are NEVER private, and almost all of them are held by other than private individuals ~ so, yeah, they gotta' give you the information. If they don't you take it upstairs to the Postmaster General.
Ordinarily USPS mail acceptance personnel (not the window clerk) are going to verify that the permit being used to mail is lawfully used by the individual or company making the mailing. They have a nationwide electronic data base to check to do that.
That, BTW, is done with each mailing, so none of these are a case of postage cheats taking mail over and just dumping it on the platform until it's taken in and worked. USPS gets paid first.
In cases where you suspect somebody is using a permit imprint improperly you can report that to a Postal Inspector.
I didn't find anything improper in any of this (40 years experience plus I wrote all these rules so I probably ought to know but I could have missed something). HOWEVER there are a number of federal laws against misuse of federal agency names, symbols or insignia ~ one of them right here; http://www.law.cornell.edu/uscode/text/18/709
The question is Soros' misuse of the address for a state agency ~ but the federales have a real problem there ~ it's a state matter, and USPS doesn't involve itself in state law enforcement EXCEPT under it's fraud against government agencies program. You might want to read the following as well: http://www.law.cornell.edu/uscode/text/18/1341
So you’re saying that if I get a piece of campaign literature from a mailhouse using say “Permit Number 123” and I ask who that is (at the post office of mailing), they have all been lying to me for way over 20 years by telling me they’re not allowed to? That is amazing. When you say to take it up to the Postmaster General, do you mean just a letter requesting the same info, or do mean a complaint form?