That sounds good until you remember the Bayesian Base Rate Fallacy: there are very few terrorists (the base rate of terrorism is very low), so filtering on "people with strong passphrases" is going to produce an overwhelming feed of false positives.

Nobody cares that you're using an alphanumeric passcode on your iPhone.

Some corps require or strongly encourage it. My employer does.

And most parents I know use alphanumeric to keep their kids from wiping their phones and iPads just by tapping the numbers. (A four digit number code auto-submits on the 4th tap, so all it takes is 40 toddler taps. An alphanumeric code can be any length and won't submit unless the actual submit button is tapped.)

Corporate email profiles on BYOD phones often enforce a long passcode requirement, so you've got a lot of Fortune 500 sales guys to screen out if you're stopping and searching anybody with a suspiciously long password.

Except that with Touch ID, you only have to enter it when you reboot the phone, or if you've mis-swiped 5 times. I've had a strong pin for a couple of years, and really don't find it even a slight inconvenience (in the way that I use a super-weak password for Netflix, as entering passwords on an Apple TV is a real pain)

People who desire to be secure in their electronic papers and effects are not and should not be considered "suspicious people".