Thought about using amplification

I was just reading Ray's blog about Paris France. Listen to what happened at the Eiffel Tower :

One official there tried to stop us by saying that we didn’t have a permit to
speak. I told her through an interpreter that we didn’t need one because we
weren’t using amplification. She backed down and said something like “Be careful
you don’t break the stone steps.” I guess she had to exercise some
semblance of authority. It was strange because I perhaps could have done
some damage if I had had a sledge hammer, and I didn’t have one.

I wonder how much amplification causes problems? At the park on Sunday, I don't think it would have been a big a deal if I would've just lifted my voice. The intensity is so much greater without amplification. However, it's rough on a singer's voice.