My bike was locked up on my back porch for a few weeks with a newer u-lock w/flat key. Just move in recently. I belief that the thieves are sweeping the neighborhood. Our neighbor's bike was stolen a few days prior. Then, they couldn't cut the u-lock that I had, so they broke the railing and must have thrown the bike in the back of a truck/van. They also stole my roommate's front tire from his bike. It happened in the middle of the day. My roommate has left his bike on that same porch for over a year with no incidents. Has even left it unlocked for weeks at a time. There's been a great deal of stolen bikes reported in Lincoln Park area recently.