If you’re using the suction handle instead of the iSclack, I’d recomment tying a band around the bottom end of the iPhone to create a physical stop to prevent the front pulling away too far. Maybe something like a couple of tough rubber bands or a shoelace wrapped around two or three times with enough give to allow you to pull up the front, but to stop the it flying open if you pulled just a little too hard.

I think a band of some kind like that should be included in the kit, it would be an inexpensive solution that allows people to use the cheaper suction handle but still safeguard the touch ID cable.