Yeah sure. I mean what are they going to do, crash it worse than me?
Back in 2011 we did the 6 hour off road team race. My buddy and I vs another friend and his dad. There might have been 80 other teams, but they didn't matter.
Since we were just doing this race for fun and not taking it seriously, I took my 11 year old YZ125 and left my 540cc Ultimate Racing Four Stroke KTM at home. The first sign of trouble that I ignored was "Hey guys check it out, I can start my bike by hand!" "Orange, that might not be a good thing."
I made it about 1/4 of a lap and the bike died. Pushed it back to the pits. I didn't drive 7 hours to ride one mile and get drunk, so I rode my teammate's 9 year old KTM 300. Pushing the bike back to the pits meant that we lost a bunch of time, and eventually got to be exactly 1 lap down from our other friend. Actual results were already out the window, but every corner was set to be an epic battle.
Until we got to the straightaway in view of the pits, and I went from 10 feet behind his YZ250 to 30 feet in front of it. After that it was wheelies out of every corner, and roost everywhere! I needed one of these.
A month later I bought a new in box 09 KTM 250. My friend saw my shiny new bike and bought an 11 300XC a week after that.
And that's the story of the $15,000 YZ125 top end, and why lending your bike to your friend at a race can be expensive.