Earlier this week it emerged that some owners of the Pixel 2 were finding the option to unlock the Pixel 2 bootloader greyed out, but in an update to the issue tracker Google has advised the issue is now resolved.
The issue with being unable to unlock the bootloader on Pixel 2 handsets seems to have been mainly contained in the US as we were unable to find instances of it occurring here in Australia with phones sold through either the Google Store (where the issue was reported in the US), or through retailer JB Hifi or carrier Telstra.
The update on the Google Issue Tracker from a Googler notes that the issue is resolved, but requires a factory reset f the phone at which time you’ll need to make sure the device is connected to the internet:
Please factory reset your device and make sure it connected to the internet during setup as this issue has been resolved.
Settings -> System -> Reset Options -> Erase all data (factory reset).
It’s probably just a by product of selling phones through Verizon in the US, who don’t allow the unlocking of bootloaders, but the ability to unlock the bootloader and then root/install a ROM on your phone is a big reason for a number of people buying a Pixel (and formerly Nexus) phone, so it’s good to see Google has resolved this. If you were affected, follow the instructions above and you should be right.