Why does this feature exist? I recently got locked out for an hour having just kept my phone in pocket whilst out walking. Ok it was warm, but given how imprecise touchscreens are, seems like this is something that could just be triggered accidentally while phone in pocket.

This feature is just dumb. Serves no real purpose. Imagine a situation where this had been triggered, you were out somewhere unfamiliar, got lost, getting close to nightfall, needed to find out where you were on the phone? Only to find you are locked out for x hours (yes hours) and need to call the emergency services as your only available option? Not a good look. This could have been avoided if not for this "feature".

Imagine brute-forcing the PIN number. Someone could manually test a number every 2-3 seconds if they were fast. Now a 6 digit pin* has 1,000,000 possible numbers. Doing one per 2 seconds would mean 43,000 or so per day (at constant rate with no sleep), 3 seconds about 29,000; the full million would take 22-33 days full time (midpoint 500,000 would take 11-16 days) with no sleep at 1 attempt per 2-3 seconds. See what I'm getting at?

Why not limit lockout to 5 minutes (likely not dangerous, just annoying) instead? By brute force that would take 150 times as long (something in the ballpark of 10-15 years with no rest for an average 6 digit pin). Wouldn't seem worth doing.

Difference is lockout for 5 minutes is annoying, lockout for hours is extremely annoying and potentially very dangerous as you are disabling the phone in potential emergency situations (besides emergency services would take a dim view of being called out unnecessarily, your only option it seems).

If you insist on keeping this feature please can you give us the option to disable it in an update. I for one DO NOT like it and want rid.

* Why would someone use 4 digits instead of 6? Either way, using 4-digit pin, divide times above by a factor of 100.