I have recently been using a small cable type gun-lock through my rear wheel and around the chain stays to achieve the same type of low-security lock when I am near my bike. Perfect example is at the barbershop. The bike is parked on the sidewalk about 10 feet from me, but if not locked in someway the theif might be able to get away before I could get out the door. The locks are typically given away free at police departments (I bought mine!) and look like this: