(edit) Would someone please ship some counterfeit money through there and get it confiscated, so the police can then be investigated for spending counterfeit money?
But wouldn’t a particular dog with particular training who then becomes very interested in your unopened USPS package be a real reason to open the pkg?
USPS is federally regulated and have different protections. Mail shipped through USPS cannot be opened by anyone other than the recipient for any reason besides a warrant. A dog indicating on your package would mean nothing to postal inspectors. Fedex and UPS are private companies and your packages do not have the same protections.
I have never heard of dogs being used to mass inspect USPS packages. I'm unsure if that would qualify as a reason for opening USPS packages. I can tell you as someone who lives in a community infamous as the source of many illicit packages (and the destination of the subsequent illicit payments), common knowledge here is to use USPS.