Many years ago I kept my Taylorcraft tied down at an airport where there was a very low budget banner operation. They had two Bird Dogs and a Stearman. I occasionally hung out with the banner pilots, and one day the owner of the operation offered me a job. I told him I didn't have a commercial, and he said, "I don't care, I've seen you fly." He would pay cash.
I actually thought about it as getting more Stearman time was tempting, but he wanted all day, every Saturday and Sunday, all summer, and I had a life (including, most importantly, a new girlfriend) so I declined.
Good thing, no doubt, as a couple of weeks later one of the Bird Dogs had an engine out right when snagging a banner and crashed on an island. Nobody was hurt, but if it'd been me, with no commercial certificate...
I'm still married to that girl.