You can build a lamp with a 35' cord, I don't see a prohibition there.
I'd say hiding it under booth seats is concealing the cord in the finish of the building, and is also exposing it to damage.
That may sound a bit nutty, let me explain. The freshly built fast food joints are looking to devote as much space to tables as possible, and reduce the amount of kitchen/office/cooler space as much as they can, to maximize the use of a new building.
It is becoming more common to store files in the seats in the dining room
to make use of the otherwise unused space. It's not as though you'll pull up a seat and find filled out W-4 forms and P&L statements under there, but you could find promotional material, outdated POP material, training materials, uniforms, etc out there. Space behind that counter is at a premium, and whatever doesn't have to be, isn't.
I am not making this up.
Dropping boxes of paperwork and old displays into that space makes it exposed to physical damage.