Chris; that's good enough for me. I was assuming that Horizon FM has no official SW license, and is a de facto pirate.
My personal feelings are that listeners should enjoy what they are hearing, QSL if they wish, and keep the speculation as to location to minimum in public. True, things are a little different if they are not in NA. There have been other stations whose locations have been questioned recently (Pirate Radio Malta and Radio Totse come to mind) and TBH, I don't really care where they are/were actually located.
Ireland or Tenerife? Don't care, they're both good catches in Chicago!
For me, knowing that you heard a station, and that they have honored you with a QSL is more than enough.