Dear George, GreatScat1965, and mid-60s Buick protectors,
Any visible device will deter the common thief. He will move to the next car without one. In experience, living in New Jersey by Newark Intl. Airport, if they want your car they will get it. Period. Unless you can bolt your car to the ground a determined carjacker will take it. I've seen cars snatched with tow mounts on the back of pickups pulling a car with the alarm still whaling.(Repo man style) The guys in the GSCA have had more than one car taken with trailer, even the entire race rig. Cars have even been taken out of their garages.
I'm not saying don't put a device on your car I guess I'm saying don't be surprised if it's gone despite all of your precautions.
Your point is well taken and a professional car thief will always be a classic car owners worst nightmare. However, you can further help yourself.
In my case, my car is very much a one-off creation that is not likely to have a market. So the professional car thief isn't likely to be interested. Even numbers matching 1965 GS aren't the most valuable cars out there, so guys on this board aren't as tempting a target.
The requirements for Hagerty's insurance represent some good common sense. If you really care about your car, keep it in a lock garage - preferably at your home so you can keep an eye on things and discourage prying eyes. When you do drive your car, try to avoid making a periodic activity. If you take your car to the same shopping center, on the same day of the week, someone might notice your car and your habit. You want to give people a chance to admire your car, but never be sure when or where they might see it again.
Nothing is perfect, but if you make your car too much of a hassle given its value on the black market, you have a fighting change to get the professional thief to pick another
"sucker."Cheers, Edouard