Don't assume an product in a pawn shop is stolen, especially if it's an audio product.
In audio, there are many so-called 'audiophile' buyers who frequently buy and sell items, often without opening them. They suffer from a condition known as
Audiophilia Nirvana Nervosa where they constantly seek perfect synergy among amps, preamps, speakers, or subwoofers. Unfortunately they don't know how to make a choice rationally, so they often decide using whim or superstition. They rarely stay satisfied for long.
For all we know, someone bought two sub woofers, intending to compare them over an extended period and keep the one he liked better. Once he installed the first one, and realized how much work & bother it was unpacking, moving them around, and repacking again, he sold the other sub woofer without opening the box.
As much as we look down on those who suffer from
Audiophilia Nirvana Nervosa, we can also benefit from them. My amps and AVR were all bought used from such people

.