Preface: I am not a lawyer and this is not legal advice and is not intended to be taken as such. Know the laws of a municipality before urban exploring.
Oftentimes, explorers will find themselves in places they shouldn’t be in. No matter the intention, building owners or operators, random passerby, and employees of nearby institutions will see people that they know should not be there and call the police. Obviously, this is detrimental to the purpose of exploring and can lead to some pretty hefty fines if not avoided.
The first thing to do when exploring is to keep your location(s) safe and take precautionary measures to ensure the police won’t be called. Make sure the right people know where you are. This may include your roommates or family members, but can also include your group of friends. But only tell those who need to know. Make sure no one you tell will call the police to your location.
Bring the right gear. Reflective vests, hard hats, and clipboards can get you in just about anywhere. Even if gaining access is simple, maintaining a cover that tells random folk that it’s okay for you to be there may not be. Wearing a simple reflective vest and hard hat is usually enough to give people the signal that you’re supposed to be there.
Don’t alert anyone of your presence. When in a drain, don’t pop up random manhole covers to get a sense of where you are. Instead, look for landmarks through the manholes, try to activate the GPS on your phone, and learn to get a good sense of distance, direction, and time. Don’t go to empty buildings in broad daylight during rush hour, don’t climb water towers or construction sites while people are working there (!!!). Go to locations when there is nobody around to lower the risk of being seen.
Be aware of the habits of the grounds crew (if there is one), maintenance, employees, dog walkers, bikers, or police. Most people and businesses run on a schedule. If you know that a cop car comes around right after Ms. Johnson walks her dog around the grounds every night, wait till the cop finishes his rounds to gain entry. Tying in to this, don’t break and enter. Enter only if entering is easy. If you have to break a window to get into a place, you’ve now possibly committed a felony, and, if you’re in the city, alerted someone of your presence and possibly tripped an alarm. No door busting, no breaking windows, and no lock picking. This helps you if you are caught, too.
So, you’ve followed this advice and now you’re in a spot. But somebody who was randomly walking around the grounds of your location happened to see you and think ‘Boy, quite odd that a construction crew is there at 10pm. I better get nosy and call the cops’ and boom, you’re now being searched for. Upon arrival of the police, stay cool, calm, and most of all, be honest. You’re not there to do drugs, you’re not there to tag, you’re not there to film a dirty movie. You’re there to take pictures and leave footprints.
Don’t run from the cops, don’t be rude, and make sure you always follow their orders. If they tell you to put the ‘thing’ in your hands down, don’t say ‘it’s just a camera’. From 150 feet away, it might look like a grenade, they don’t know. Don’t give them a reason to tase you, drop your camera. Be compliant.
If asked to leave, leave. If arrested, shut the hell up and wait for a lawyer. This is crucial. In most jurisdictions, a cop can only request someone to leave if the property owner has requested it. While under arrest, this is not the time to ask the cop who called and requested you to be removed. The time to ask that question in court with a lawyer present. In fact, your lawyer will be the one asking that question (probably). Don’t resist arrest. The less of a pain in the neck you are to the cops, the less chance you have of actually being charged, the more chance you have of being given a warning. Also, the less of a pain in the neck you are to the cops, the less likely they are to actively search out other explorers.
Security is kind of another risk. They patrol areas pretty regularly and have their own set of rules they operate on. Much different than the police. They don’t care if you’re there to take pictures and leave, you’re not supposed to be there, and they will do everything they can to remove you. Sometimes they will be nice and tell you to move along, other times, you’ll have to bounce pretty quick. Side note: though running from the cops is discouraged, running from security is another story. They (usually) can’t shoot you and most of the time the most they do is tell you to leave and call the cops. The biggest thing to avoid is being seen or noticed by security.
Hopefully, you never have to deal with cops or security. But if you do, hopefully the cops take it easy on you and understand. For a first hand account of the cops appearing somewhere (and a grain of stupidity), read this link