mechanic's lean

To quote wikipedia.com: "A mechanic's lean is a security interest in the title to property for the benefit of those who have supplied labor and/or materials that improve said property. The lean exists for both real property and personal property. Said security interest entitles said mechanic to physically rest his back or shoulder against said item of property (resentful scowling and indignant arms-folding optional) until such time as said property's owner shells out correct payment for said property-improving labor and/or materials."

The primary purpose of outlawing running-boards on most modern vehicles was not for safety-reasons; it was to discourage garage-repairmen from performing mechanic's leans on said vehicles while people were trying to drive around town.