David Schütz found a great lockscreen bypass bug on the Google Pixel. All you have to do is to hot swap the SIM card with one, you know the PUK of. Type in three wrong PINs, then just enter the PUK and the phone goes straight to the home screen.
Imagine that this is something, the FBI fought Apple with tooth and nail for.
There’s a reason why I keep telling people not to bother with lockscreens, but rather consider their phones to be a portable version of the computers in a public library.