I have this happen with my front wheel all the time. Drives me crazy when I head out and get a little ways into my ride and hit a bump and hear it. Not a huge deal to stop and fix except for my crappy cyclecomputer which is a pain to get reading the magnet again.

If I remember to, I usually bounce the front end a little in the driveway before I head out to make sure it isn't loose.

To clarify, "tire tube" sounds like the tube inside the tire. The axle nut is what is being referred. The nut holding the axle and bearings together, not the quick release.