I put a stock length rubber ducky on my piped plane and reduced the oil presidue to where it would be a one Kleenex job, at most. Just a little smutz on one side of the fuselage under the stabilizer and behind the tailwheel strut. No big deal...
Can't name names in this situation, but somebody had an almost unnoticeable slight prop strike on takeoff and their electric motor shut down...KR timer. I think I was launching, and I didn't notice the "bzzt" sound. Didn't know what to think about that.
Have seen a couple of electric motors smoked, many batteries smoked, prop drivers come off, motors not start, timers not set correctly, ESC's not set correctly, two motors come flying out of the front of the plane, and a few emergency shutdowns. It's a new game, and all the stuff needs to be correctly done. Details matter.

Steve