I don't suppose there is much expansion of iron or steel disks when hot, but there will be some. This means that when the disk and pads cool down there may be a fraction of contraction and, perhaps, a fraction less grip. If the grip is marginal in the first place a fraction less grip may be all it needs to start moving on a steep slope.

My feeling is that if one has any doubts at all the wheels should be turned towards the kerb and if there is no kerb a chock may be advisable. In any case always leave the car in first gear, lock it, and put the tonneau cover on (or hood up) to discourage any idiot from getting in the car for a photo.

No doubt sooner or later there will be a fix for this issue.

Peter

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