I would never provide this info, a main reason I have no vehicles listed on MAFFI. That also includes frame numbers. Too many lawyers, too many taxing and regulatory agencies, too little time.
I have a pile of 50 year old unsurrendered titles from various states, no vehicle to go with them. Let's see what number pops up, and how many hundred law firms would like to go after the vehicles on a contingency basis.
If one of the numbers for an open title I possess pops up, all you have to do to retain your (?) legal possession of the vehicle is provide a complete paperwork trail through all previous owners back to the title in my hand, lest the vehicle be mine. You did keep a record of all previous sales and transfers to protect yourself against such claims, didn't you???
I'd rather give you my Social Security number.