the police can come and arrest you for trespassing
Quite possibly wrong but I have always thought that one had to prove damage for a trespassing charge to stick?
A Sydney, Australia lawyer, told me very recently that it is an offence to photograph someone without their permission, being careful to draw the line between deliberately taking a persons picture, without their permission and taking a picture that included a person but who was not the object of the picture. This was all related to drones but the lawyer did say that certain laws about taking a persons picture applied across the board . The photographer on the Ryan Air aircraft was, I think, without a doubt, photographing the man who was engaged in the dispute.
IF the audio and visual here is illegal would it be inadmissible too? As soon as the defence can get two or three witnesses contradicting each other the case would surely be lost?