Accidental actuation of the brake lever while the wheel is removed probably doesn't depend on whether it's flipped. There have been plenty of threads here admitting they grabbed the lever intentionally or unintentionally while the wheel was removed and popped the piston loose.
I guess we need to go back and ask if the bike was flipped or not. <grin> Well, not really, but I'd think if someone else was helping you. And one of you was holding the frame upright, then when trying to keep the front wheel from rolling the wrong lever might be pulled.
So it's a toss up. If you want to be careful, then find a piece of cardboard or plastic or something that is the thickness of your disc and secure it in there with a rubber band or such.
At least by having to remove it before installing the wheel, you'll be reminded to be careful of the brake lever.
Last edited by Iride01; 06-12-20 at 12:56 PM.