What if it did glitch on the runway?
What if it did fly to the crowd?
What if it plopped itself down?
What if a jet glitches hundreds of feet high?
What if it flies straight down?
What if it lands in the crowd?
What if the most experienced guy in the world, has a structural failure in a small trainer?
What if a microscopic crack in a servo gear grows untill it strip, crashing the plane?
What if I trip on a stair, fall back, and break my arms legs and spine?

Anything could happen, any time, anywhere! So I don't think that argueing if it is safe to hover has any point. As everyone said before. Just say 'excuse me, do you think I could have a little flight to myself to practise some hovering?' There you go, problem solved. (As long as you don't do it every two minutes!?
My 2 cents in there too!
Robert.
Keep safe!