My wife used to lock her keys in her car all the time. One time she called me at work on deadline (I was a newspaper reporter at the time) and wanted me to come open her car. So I drive all the way to the grocery story where she was shopping, open her door, and the key wasn't in the ignition. Turns out she had dropped it in the parking lot, and somebody turned it into the office. I now tell her to call AAA when she locks herself out of her car; we get our money's worth out of our membership. BTW, I've been known to lock my keys in my truck (very rarely) but I keep a spare key in my wallet, so it doesn't matter.

Oh yeah, keep up the good work on bike commuting. Occasionally things will come up to make it inconvenient, but in balance you will be glad you do it. When I started bike commuting, my plan was to ride one day a week, on dress-down Fridays. Now I'm riding 4-5 days/week. It's habit forming.