If one had a warrant then you just force the suspect to give over. Just like forcing them to give fingerprints. Isn’t the whole discussion moot if they have a warrant?
So when you offer a path to get into the phone without a warrant it’s just like breaking into a “house” without a warrant. Technically easy - just go through the window or use the fingerprint from booking. It if we agree with due process either is wrong.
Is it cumulative? Or is it probability — which of course goes up if you shower yourself in radiation multiple times a day?