Monkey-Wrenching The Co. Parking-Lot Tyrants
Patentnonsense has nailed this dead-on by referring to this invasion of privacy by politically-correct/anti-gun corporate lawyers as tyranny. Viewed in a practical sense, these policies simply do an end-run around (and over) the 2nd Amendment... and basic rights of self-defense AFTER you've departed the parking lot.
Accordingly, suspend any qualms about "fighting fire with fire" (at least until new state laws abolish this leftist bull****) via smart "monkey-wrenching" subterfuge.
Suggestions:
1. Stow your Car Gun and ammo in an air-tight Pelican case... and inside a second locking case, such as a good briefcase or tool-box.
2. Keep the gun VERY clean, and free of powder residues and excessive lubricants. This also applies to the storage case... and it requires frequent, more-than-casual cleaning, lubing, and airing-out.
3. Keep some opened/partially used , moderately "leaking" cans and jars of various common auto lubricants in your trunk or pick-up bed. If the dogs "find' this diversionary stuff, it's no big deal.
4. Occasionally spray one of your tires -- and OTHER nearby parked-cars' tires -- with O.C./peppergas. I love my dogs, too, but I've also had good results with O.C. against feral/attacking dogs. They generally hate the stuff. Be real discrete about this, and watch out for parking-lot surveillance cameras. Even at $15 a canister X monthly, this is a cheap investment in protecting your butt and your 2A rights. It's also a good use of old/expired O.C. canisters that need to be replaced, anyway. Besides, if you get "busted" for this, you can simply explain that -- since they disarmed you AND you *ahem* certainly wouldn't want to go against co. gun policy -- you've recently had to use O.C. on a would-be car thief... just when the co.'s progressive, "anti-violence" lawyers wern't around to protect you!
Others here might supply their expertise and imaginations to invent more refined ruses and diversions. Beyond that, I fully realize this approach is not "The High Road". However, The Great American Gun War has long been fought by the Anti-2A's playing cute political games, media-manipulation, and being "offsides"... without penalty.
So, until their self-righteous, underhanded games are blocked by the next round of pro-2A laws -- consider playing "offsides" selectively. If enough folks do this successfully, it'll frustrate "them", force more politicians to show their true colors, and hasten the anti-gun liberal crack-up.