enough that the sheriffs in my area waste tax money at hauling big construction signs, park them near parking lots, and turn them on 24/7 to remind people to lock or hide their laptops.
Indeed. Whenever I travel I lock my laptop in the trunk. In my car the trunk can only be opened by the remote attached to my key (or by someone with a really good crow bar or chain saw but that would cause way too much noise).
it's a called a trunk and valet keys. use them.