There's no way it's VZW making Moto encrypt the bootloader. Moto is the only mfg that does it so I'm not sure why things would be any different. If this were the Moto Galaxy Nexus, then we'd have reason to sweat it!
Verizon doesnt have the resources (thankgod) to encrypt bootloaders. They make the recomendations to the manufacturer. Encrypting a bootloader means its Locked. Nexus devices are GED Dev devices and therefor require the bootloader to be accessable. Every other VZW device has some sort of lock on the bootloader, except D1 and Xoom. Others may be unlocked via third party or HTC allows on some via web, but not ideal.
Yeah I think it is just a matter of Moto's security being better than the others. I really wouldn't worry too much about this phone being locked/encrypted like the moto phones. Just my opinion, but I feel like we are forgetting that this is a Nexus...