Airprox definition:
An Airprox is a situation in which, in the opinion of a pilot or a controller, the distance between aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved was or may have been compromised.
Personally, I don't believe that a helium balloon counts as an 'aircraft' and the worst that could have happened is you bursting its bubble (sorry for poor quality joke)
