I'm an owner, and can see this forum, so I don't see how moving it to the iFly Owners Forum would get more traffic.
Based on what I seem to remember from the first group buy, the deal wasn't specifically limited to iFly owners. I seem to remember that some individuals posted notices to other venues. Perhaps I remember incorrectly, I wasn't paying THAT close attention.
If, in fact, Skyradar is specifically limiting the group purchase to iFly owners, it would seem prudent to move it to a forum only visible to iFly owners. If, on the other hand, it's open to anyone that wishes to purchase within the defined time frame, it would be helping the group to get a wider audience through a forum where anyone can see and/or post. In that case I would think it should be kept or moved to a public forum.