If you can discuss on the other posting I have done on this, but I would say this is seriously dangerous to both helicopter and balloon...
(thread here)
http://www.pprune.org/forums/showthread.php?t=279241
HEILIGENDAMM, Germany, June 8 (Reuters) - Police helicopters forced down a Greenpeace hot air balloon on Friday as the environmental group took to the skies to try to get its message across to world leaders at a G8 summit.
Police helicopters enforcing a no-fly zone around the summit in the Baltic resort of Heiligendamm swiftly circled the balloon, creating turbulence and forcing it to land in a field some 20 km (12 miles) from the venue.
"We were hoping to fly in a petition to the G8 leaders demanding binding targets for CO2 cuts," aid Svenja Koch, a spokeswoman for the environmental activists.
"But unfortunately the police forced us down. Their helicopters caused too much turbulence and it wasn't possible to continue."
Read more:
http://www.alertnet.org/thenews/newsdesk/L08400219.htm
I would say this is endangering an aircraft in the eyes of the law, and what legal powers does a police helicopter have to force a balloon down?