Ah, gotcha.
When the wife and I left for a few days, I took one of my unused gun locks (the kind that has the flexible loop and a padlock), and ran it through the holes above one of the wheels.
On the topic of what to do to your house when you go away for a few days. Turn off the water. I had a plumber tell me a story about some guys pipes froze because the power went out. The water kept running for days.