I am a new and upcoming parkourist and free runner and I have many questions on trespass. I fully understand you can't go on a train or on other government lands under Property Law. I also accept not to go to places that are obviously signposted, and I know to move on as fast as possible if asked by police or security. But can I go to places such as an apartment complex to do a bit of parkour, or do I need to ask permission to enter any property?