Hi Steamship,
You are right. And wrong.
Not worth the messing about was the underlying message...
"We aren't insured", "if our job is fouled by LPG piping we will stop, give you back your half dismantled car and still charge you". Oh, right, you really want this job don't you...
Thing is, let's get businesslike. I think many garages take on high risk jobs 'cos they have a relationship with the car owner and keep the simple, oil-and-filter-let -the-apprentice-do-it jobs for ages after.
A Towbar shop sees you (maybe) 3 or 4 times in your life, maybe never again. If I don't go to that fitter ever again they won't even notice.
BUT if it went pear shaped...
Just business.
YB