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

Engraved info: grab a dremel tool and grind it off after stashing the loot in your hideaway. Ahhh a 2" long 1/4" wide smooth scratch on the back or bottom is not going to stop some dude from buying it out of that infamous 'white van' is it? And with ten minutes work all your dreams of marking your stuff for life fly out the window.
However: the police stopping some dude in a hurry, with a Plinius etc in the trunk: the markings on THAT, at THAT moment, might help get your stuff back. heck, don't you all watch "COPS" on TV?

sorry I couldn't be bothered reading the other posts...

I'm completely bewildered by your post and why its a requirement to write your license # on your gear.
Do you think they won't allow you into the group if you don't do this?
What good is your license # on the gear anyway? Insurance will cover it...

I would take off a percentage of the sale value for this defacement, probably in the 5-15% range depending on where it is done.

Obviously, you engrave it, you've destroyed it, pure and simple.

I am genuinely encouraged by the sensitivities displayed above by twl, asa, slipknot and others. This is seriously Orwellian stuff (more than Hegelian, if you ask me, since I think Hegel was interested in finding truth through dialectics, but I digress), and people need to examine what we are giving up in relation to the perceived threat. To turn a phrase, just because they are out to get us doesn't mean we aren't paranoid. Not only does the Patriot Act have a searingly ironic name, it's actually an acronym. It's the USA PATRIOT Act, meaning the Uniting and Strengthening of America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism. This includes reading your email without a warrant, by the way. Paranoid and arrogant behavior around the world is why they hate us to begin with, and we just keep coming up with more medecines that are worse than the diseases.

Neighborhood watch due to sniper deaths? Phillip Morris (I refuse to say "Altaris") and Ford killed 1,000 people in the time those guys were shooting up your town.

My advice is not to mark up your gear. Don't concede the point to the thieves. Chances are tiny that you'll get ripped off and the markings aren't likely to help much anyway. If you want protection, get a dog. From a shelter. Win/win.

By the way, I would still buy your gear, but I would pay less for it than if it had no markings.

I don't have an opinion regarding engraving audio equipment. I do, however, think that every congressman and senator who have received campaign contributions from the NRA or gun manufacturers should have their foreheads engraved with the same.