It's not illegal to sell a non-UL machine in California, but the will of the insurance companies is good enough that nobody's quibbling.

Many years ago the outfit I was buying power supplys from dropped the UL approved line. I dropped them like a hot potato. They tried for years to get my business back.

"Why you not buy from us?"

"You dropped UL approval, so I buy from this other guy now."

"But all our power supply UL approve now."

"Yes, but we only change vendors when we have a compelling reason. You gave us a compelling reason. This other guy hasen't, so we're staying with him until he does."

Thumb print steel I have seen. The very worst is thumb print steel with metric screws. Every time you work on one the screws all strip out. Fortunately the steel is so soft any American screw is a "self tapping" screw.

Everybody went to metric screws about 8 years ago, but all the good cabinet makers went back to American screws in a few months.

We use Super Power cabinets. They're stamped out of light gage boiler plate. You're thumb is going to hurt real bad if you try to print one.