This is pure speculation on my part, I was just thinking about the fact that fictitious return addresses could possibly get packages flagged for inspection. If a vendor used a different customer's address as the return on your package it may eliminate the chance of the package being inadvertently returned to a random person by accident, and some lucky former customer gets an unexpected gift.
Is it even a feasible idea?
They could but they shouldn't. Having a return address not be in the same area as the processing post office is major red flag for LE.