Motorola has responded by putting those fears to rest.

From Engadget:

Motorola’s primary focus is the security of our end users and protection of their data, while also meeting carrier, partner and legal requirements. The Droid X and a majority of Android consumer devices on the market today have a secured bootloader. In reference specifically to eFuse, the technology is not loaded with the purpose of preventing a consumer device from functioning, but rather ensuring for the user that the device only runs on updated and tested versions of software. If a device attempts to boot with unapproved software, it will go into recovery mode, and can re-boot once approved software is re-installed. Checking for a valid software configuration is a common practice within the industry to protect the user against potential malicious software threats. Motorola has been a long time advocate of open platforms and provides a number of resources to developers to foster the ecosystem including tools and access to devices via MOTODEV at http://developer.motorola.com.

What it means is that the e-Fuse will shut the Droid X down if you try to run an unapproved bootloader. But, it will not brick the phone.

So for those worried that Motorola was taking a hardline approach with the Droid X can breathe a sigh of relief.