Many people "hear" with their eyes. If they see acoustical instruments, they consider it acoustical even if sound reinforcement is used.
On the other hand, some years ago I was hired to play an outdoor event on lute, so naturally I brought a tiny amp. When the park's official saw my amp and said that amplified music was not allowed in the park, I asked her to listen to my instrument from 10 feet away. When she couldn't hear it at all, I was allowed to demonstrate my amplified sound, and an exception was made. Needless to say, the people who hired me were relieved.
On a final note, definitions are constantly shifting on many subjects due to terminology, technology, public perception and acceptance, etc..
On the other hand, some years ago I was hired to play an outdoor event on lute, so naturally I brought a tiny amp. When the park's official saw my amp and said that amplified music was not allowed in the park, I asked her to listen to my instrument from 10 feet away. When she couldn't hear it at all, I was allowed to demonstrate my amplified sound, and an exception was made. Needless to say, the people who hired me were relieved.
On a final note, definitions are constantly shifting on many subjects due to terminology, technology, public perception and acceptance, etc..

