I agree in general but on the other hand, isn't removal of unauthorized private property from public lands a routine duty of local government employees? So if anything I feel like flock is lucky the cameras weren't physically destroyed upon removal.

For example, if a maintenance worker had been instructed to remove them how would this have played out?

The cameras would have been removed. Munis don't generally destroy random tech infrastructure they pull off poles, though they might throw it in a big pile. Flock could invoice for the cameras, but most munis would probably tell them to go fuck themselves.