yea this was in my infancy of moped repair, didnt understand how those chain tensioners/wheel aligners worked. so i basically just didnt use them, and apparently didnt torque the bolts down hard enough. eventually i hit a bump and im not exactly sure how, but my theory is that it jostled the wheel enough that it came out the front of the little recesses for the axle to sit in.
next thing i knew my chain broke as well as the brake cable and the wheel was resting uncomfortably between the swingarm and the fender. grossss. i was only going about 15-20, though, and travel with tools. so i was able to patch it up just enough to get it home.