I guess I didn't state it properly. I said 15,000ft. but should have said 15,000ft out not round trip. The video I referenced wasn't a flight distance type video. He was on his way to look for a house up on a hill that had reflective windows. He said a couple of times each year the house would send a glare towards his house. He said it was between 2-3 miles from his house and he wanted to see which one it was. The distance wasn't brought up until he turned due to the go home warning sounding.
No worries, I see the same sort of post everywhere about how someone with the tin foil job had to turn around at 4kms because of battery concerns while I know the battery is actually good for close to double that. Im just waiting for someone to give the windsurfers a real test and not fly mostly over water or turn back kilometres before true battery range. As it stands I have friends who manage 4.6 miles on the stock system so Id like to see a few distances like that and I'll become convinced of their merit.