This happened to me once on a no-drop ride around LGT. There was only one group going the full distance, and that was the fast group. I had never ridden LGT before, but had done plenty of 7+ hour Epics in the Cascades, at my own pace. We started at Tejas so the first few miles was flat out sprinting for these guys. By the time we had to start climbing, I was gassed. The sweep asked if I'd be able to keep up and I said not at this pace; so he told me I'd have to go back. I'm like, "hey dude I'm 55 yrs old and I think I'll just continue on at my own pace by myself". I ended up doing a 20mi out-and-back that took everything out of me. Last year at DS and at 60 yrs old, I did a full lap in 3:17, and thought back to that fateful day when I got dropped from a "no drop" ride.