Yes- I've made TONS of tack and would oftgen have people just send horses to me via contract to put tack on. Then I would notice that my inventory of tack would at times mysteriously increase because people would remove that tack and it would come back to me.
If I offer tack sets- usually will do it for free if I have time. But mostly now I just list the tack on the marketplace so that it doesn't come back.
On a positive note- I can randomly clear out 'tack packaged' horses that have been sent to retirement

as they do show up on my inventory as being used by XXX horse.
Duct tape is like 'The Force'. It has a light side and a dark side, and it holds the universe together.