Well.. heh.. if the postal police did get wind of it, they won't make any appointments or send you letters - they'll be paying you a visit with local LE. I took a tour of a BMC once and was shown their area of confiscated items - everything ranging from packets of blood? to large trees? to everything else under the sun that either couldn't be delivered or was some type of contraband. The guide told me they also intercepted 3 bombs during his 10 year tenure. I think they too (postal police) have a lot on their plate right now too, like the DEA.

Additionally, the sorting centers have enclosed catwalks overhead - with one-way mirrored windows encompassing the entire sorting area to discourage theft. That's where the postal police keep watch on the sorters when necessary I suppose.