+1 to the no comment. I know it feels bad, since we all can relate to the situation, but a $5k/$10k/$20k+ instrument? Nope. Nope, nope, nope. I don't even let anyone check out my SCSD unless I know them well.
I wouldn't be opposed to loaning out my backup, if I had one at the time, but not a primary. Of course, my usual backup/second bass is my NS Design OmniBass (fretless), so that usually scares the crap out of anyone who asks.