Never seen this on any car before, didn't even know it was a feature(?) on EF Fairmont,
Only noticed this the other day, In daylight,engine running, lights not on ,when I hit the brakes, parkers come on, also does this when car is in reverse(not touching brake)
Repaced a brake light bulb on let side recently, noticed that the reverse bulb socket on this side did not have a bulb in it, stuck one in at same time,wonder if this is connected? They are suposed to have reverse lights on both sides aren't they?
If it is a short it is a very well thought out one, sort of makes sense.

hmmmm that's weird never heard of it happening before myself, I would guess that you've got a short somewhere, how hard are you hitting the brakes?

and yes meant to be two reversing lights from what i remember

not "hitting" brakes, the pressure required to turn on the rear brake lights is what turns on the parkers, no brake at all to get the parkers on when reverse is engaged

You have a faulty earth on one of the rear light assemblies or there is a short in the bulb holder.

or an incorrect or shorted bulb

yea not normal man

IT was a short, took both rear light pods out, checked holders and bulbs. the side I hadn't touched had a single filament no offset bulb forced into brake light holder, replaced...."safety feature" gone .