People will freak out... but I don't lock my phone. Never have.
It's either in my pocket or in my hand, and I never ever put it down in public. If get mugged (god forbid.. and do people still mug other people for phones these days?) there's nothing mega personal on it, and I can remote erase it pretty quickly.
Where do you live? Any urban center anywhere in the world phone theft is common.
I live in Dresden (Germany), and I've never even heard of anyone who has been mugged here. Sure, there will be cases in the statistics, but I can not name anyone who has been mugged, ever.
Theft is a superset of robbery; I know plenty of people who have had their phone stolen because they left it lying out in the open
A fingerprint lock is way more secure than no lock.