My son was taking care of a neighbor's dog while they were on vacation and locked the key inside their house. I was not able to contact them on their cell phones and could not find a neighbor who had a spare key for them. I was about to call a locksmith because we can't leave the doggie locked inside (!) when I decided to google "how to open a locked door with a credit card."
I looked at the directions, went to their house with an assortment of cards (library card, frequent shopper cards, etc.) and popped that lock in about 2 seconds! It was actually kind of scary how easy it was to break into someone's house.
Grits
2010 Trek 5.2 Madone WSD, SI Diva Gel Flow
2002 Terry Classic, Terry Liberator