Yikes, you flew with someone who didn't sump the tanks? It's so universal
that it would make me wonder what else he wasn't doing. Were you there for
the whole pre-flight or did you just get in after the plane was ready? I'm
sure the tanks were checked. I've heard of a lot of dumb flying tricks but
never not checking the tanks.

The sumps are a valve that opens when a rod is pushed in. There is a nifty
little jar with a rod held in the middle so that the fuel pours in. You
then check for the proper color, sediment, and water. It used to be that
you then threw it on the ground and many still do. Because of the lead,
more and more pilots are now using sample jars with a mesh screen that
filters out water so that the fuel can be poured back in the tanks. You
want to visually confirm their level anyway.

--
Roger Long