YES! Chkkkkkkkkkkd
They also report suspicious behavior when asked, and they get asked a lot.
About things such as new pets, lifestyle issues, even if you add a patio on the back of your house the tax man magically finds out - usps carrier likely wanted a kickback from a tax authority. Fuckers are paid spies and brainwashed to do it as part of the job unknowingly for the most part.
It is common for investigator to ask postal worker about the habits or such of a person on his route.