Law 8: The likelyhood of any small part dropping and becoming lost is inversely porportional to the likelihood of sourceing a replacement.

Law 9: Even if you can source a replacement, you won't recieve it for 2 days and the bike absolutely has to be ready tomorrow.

Years ago when I took my 12 year old grandson with me to do tech support on a big week long ride the first thing that I taught him was to put a tarp under the workstand whenever you set up on grass.