This topic has been popping up more lately. Back in the day HUO was about less than 5% of the resale market. Fast forward to post 2010 and the number of HUO pins of that year or newer has increased dramatically. Add to that new people in the market and the water gets more gray by the week it seems. Some honestly believe they have a HUO machine without anything more than what the last seller told them. I had a friend buy a machine HUO from a reseller only to find a token in the coin slot.
Recently I saw a JM pinball being sold as HUO and questioned the seller softly (asked for pictures). The guy that sold him the pin contacted me via PM and said it was a route pin he had sold to the now seller back in 2003.
Buyer beware condition is king and HUO means very little IMO.