A good flat-bar, hacksaw and a pair of Vice-Grips, for holding the lock or chain as you cut, will get you by most doors, windows, padlocks and chains very quickly. A friend used a high-end chain and padlock to lock his motorcycle and then lost the key. Even though the 1/2" chain was touted as being 'resistant' to cutting it took all of thirty seconds to saw through both sides of a link once it was firmly clamped and held in the Vice-Grips.

I've heard that it may be an idea to carry several resettable combination padlocks may be useful. If you have to destroy a landowner's lock you can contact them to tell them the combination. Once they know the combination they can reset it to something different so security, such as it is/was, is restored.

There are legitimate reasons for various people to gain access to search, turn off power and gas, check for pets and fire, etcetera. One of the main objections to such activities is that they often leave the structure open to the weather and casual intruders. Many people who would not break into a home will feel much more willing to enter a house if the door is left ajar.