The Huawei Nexus 6P has finally come to full release status and may already have a bit of a problem. Historically, the Nexus line, Google's own customized Android experience devices, have been ideal for developers and custom ROM lovers. The Nexus 6P may change all that with what seems to be a sort of virtual fuse that is permanently tripped when the bootloader gets unlocked. The implications of this are unknown at this time, but a feature like this doesn't show up by accident. As the new Nexuses are the first devices to sport Android 6.0 Marshmallow, which requires full encryption to be on by default, it's not a stretch to think this has to do with device security more than any possible warranty. Android Pay, being incompatible with rooted devices, may play a part here as well.
Some devices have features like this and can easily be reset through unofficial means, such as Samsung's Knox and Flash Counter in the bootloader. As of this writing, it seems like there is no way to reverse this for the Nexus 6P. Bootloader unlocking, being par for the course when using custom ROMs with just about any device, is possible on the Nexus 6P at this stage, but methods are still primitive and development teams are still hard at work providing benefits for said unlocking.
This could all be a premature panic or a scare tactic of sorts, meaning nothing in the end. For the time being, Google has not made any announcement concerning this find and its implications. Given the company's focus on security becoming clearer and stronger as Android progresses, it wouldn't be entirely shocking if these developments did have a powerful implication later on, such as with updates or encryption.
Whatever the case may be, let this post serve as a warning and an indication of Google's new direction with Android. With any device, unlocking the bootloader carries risks, often voiding the warranty or crippling certain functions. Most of the time, you will find protections built into a given device to prevent or keep track of modifications and these protections are not always easy or even possible to circumvent. Keep that in mind if you decide to modify your shiny new Nexus 6P.