In the US the 500' rule does not apply to helicopters as long as they do not pose a threat to persons or property. Its a bit open to debate on issues like that, but I think a citation would be possible and certain unless they were all willing participants.
On another note. Go pros use a wide angle lens that really distort things, attach one looking down a 50' longline and it looks like you are 200' up. Its also why those people look tall.