Insurance is not just to protect you, it also protects the customer as well.

A few years ago a driver pulled in front of me while I was cruising my bike (motorcycle), which I then proceed to T-boned at 40 mph. The idiot driver had the state minimum insurance, which didn't even come close to covering my medical expenses.

Heavens forbid something goes wrong with a frame someone built, but if it did and the rider got hurt wouldn't you want to make sure the person is properly taken care of?

After my accident I upped my auto insurance to $1M for personal injury. Upping the limit was just an incremental cost on top of the regular insurance cost. Just hope to never need it.