I'm seeing a lot of moustaches on cars, but I have not heard why people are putting them on the cars yet

Elias has an answer in the comment forum, http://blogs.kqed.org/pop/2013/08/13/behind-the-pink-mustache-is-lyft-good-evil-or-something-else-entirely/  a pink mustache is something to do with a new cell phone app and people that want to make some cash or online credit in a system where (like paypal maybe) they get paid tax free for being a driver. No taxi token that costs 10's or 100's of thousands of dollars. No boss. No taxed income