This has actually happened to me. I had my SUV (back when I owned one and gas was cheap) in the shop and when they returned it to me, I was driving it and noticing a sort of "clunking" noise. I called the shop and they told me to bring the vehicle back in the but couldn't fit me in until 2 days later. Well, I found out that evening, going 40 MPH down a busy highway in rush hour traffic, that the "clunking" noise was the sound of my entire wheel/tire ensemble ready to come off. And it did. And my tire bounced across four lanes of traffic. And THANK GOODNESS no one was hurt. Not tightening lug nuts seems to be more of a problem than imagined. YIKES.
Lori