I think it gets said every time these questions are asked, common sense and courtesy goes a long way. I regularly fly on the Sefton coastal in various locations some can be busy at times, I have always opted to take off and land in as quite a spot as I can find I have never had an issue, yet I only found out last week from a post on here that as the Sefton Coast is a SSSI any flights are prohibited.
No doubt if I started taking off in busy areas flying low near people trying to relax or play on the beach I would soon have a warden or a police officer feeling my collar.
I am also confident that if a warden or officer was to stop me I highly doubt this would end in criminal charges I am sure I would be asked to move on, and I would do in a respectful manor