Non-supported is a term used for bugged items which may be repaired in the future. There will be no compensation if the item is deleted or altered.
"OK, I'm going to respond publicly, since there's a bunch of confusion about the issue. This particular item is "non-supported", which means it's bugged but not (subject to be Suspended or Banned for its possession). If we ever fix these items in the future, you're plain out of luck - we won't reimburse in any way. However, we aren't taking any other action against them at the moment - we won't fix, delete, or reimburse for it." - Jeremy, UO Community Coordinator