would this Deter you from buying used gear????

Marking up our possesions with SS numbers, DL numbers etc.?
Please. Any piece of gear has a serial number. That number is generally written on the bill of sale from the dealer. This, along with a well written rider on your insurance policy is more than enough to ensure payment for a claim of stolen property. Defacing your equipment in this manner will NOT deter anyone determined to steal it, whatever their motivation for doing so might be. If you need to mark your equipment, do what the dogs do: pee on it, to mark it as your territory ;)

TWL -
I had to follow up your Hegelian Dialectic comment: Well put! We are halfway there already. A good indicator is to have a look at the text of the "Patriot Act" (quotes intentional), Internet filters in our libraries. One man's income tax is another man's payroll check. Your rising health care costs are someone else's free health care. All the while we run around, looking for spooks under every bed, each day jumping from one "world axis of evil" leader to another in an attemp to divert citizens away from the issue of ever eroding civil liberties. First it was Khomeni, now Khadaffi, Saddam, Noriega, a Somali Warlord, Osama, back to Saddam, Oh oh - now those North Koreans are starting to look evil. We need to erode your privacy and rights to PROTECT you from the boogie man du jour.
Sorry for the rant....