Liability, yeah, just let me finish signing this pile of logbooks on my desk, and we'll talk about liability. When I rebuild these old ones, my name is in there forever. I'd be better off if I could remanufacture them as "new" planes, then it would go away after 25 years.
I think it was in AK, a few years ago. A mechanic built a Super Cub up from parts. Instead of certifying it as a new plane, he put on a data plate, and used the paperwork from a wreck. Somehow the Feds got wind of it, no slap on the wrist fine or suspension, they revoked his ticket. He did fight it for all he was worth, I think what they tecnically got him on was falsifying the total time. He used the total time from the data plate/paperwork doaner, but could not establish a time on his pile of parts. But it sounded like they really wanted his ticket, and could have had it on any number of charges.
On the serial number plate that is on every Piper fuselage, sometimes you have to remove it to do mods/repairs, ALWAYS put it back on. If this plate/number is ever lost you are screwed. This is the fuselage S/N, and is different from the aircraft S/N. Having/knowing this number is more important that having a data plate. I like to write this number in the aircraft log, or somewhere safe, just in case.