Hmmm, IIRC, licenses are not needed for battery operated helicopters, but i'm not sure about the nitro helis. But, if a police car rolls by, they won't stop you from playing. They will just check to see whats happening.
I read an article in which a remote control helicopter pilot was flying in an open field, when a police car and an ambulance stopped behind him. It turned out that a person from a distance saw the helicopter disappear behind a building, and thought that a real helicopter had crashed, and as such, called the Police and Ambulance. But this didn't happen it Singapore. IIRC, it was in the US or Canada.
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