Well, a whole new braking experience. Phantom sort of implies 'for no visible reason' and it wasn't really that.
In a big parking lot, traveling around 2 mph with both hands on the wheel and no AP, TACC, FSDb, etc. - everything possible turned off, driving like it was a 1930 Chevy, met a car traveling around 1/2 - 1 mph, well centered in their lane and not doing anything worrisome. My MYLR slapped on the brakes, jumped into 'P' and plastered my passenger against the windshield. It wouldn't respond to accelerator of course and wouldn't let me out of park until I also stood on the brake, so it took 3 or 4 tries to get a 'D' and I could get out of Dodge. Fortunately, the person behind me must have had their foot on the brake, because they were only around 2 feet behind me and stopped quick enough to avoid a collision. They lay on their horn until I vanished over the horizon, but hey, I certainly don't blame them.
This ends the feeling fairly comfortable that I can always get out of a phantom braking by punching it. Just have to watch for oncoming vehicles and try to focus on getting back in drive - then punching it. Be careful out there, apparently there are surprises still lurking.