bart is quite expensive, some people cant afford the muni fees, or dont want to so they just fare evade. the inspectors are extra aggressive in giving people the ticket, but many people will give fake details so it doesnt get sent thier house, NEVER give your ID that can identify you r personal details.

as long as there is no peace officer(police) you can just try to walk off the bus and exit on a stop they dont chase you. might be harder on a BART station though.