It's possible to install a GNU/Linux environment on a Chromebook using Crouton. The first step is to put the Chromebook into developer mode, as described in the article "How to Enable Developer Mode on Your Chromebook" by Chris Hoffman. But every time you turn on a Chromebook in developer mode, the Chromebook firmware begs the user to wipe it. Here's the exact wording that the firmware displays:
The first screen (screenshot):
OS verification is OFF
Press SPACE to re-enable.
The second screen (screenshot):
OS verification is OFF
Press ENTER to confirm you wish to turn OS verification on.
Your system will reboot and local data will be cleared.
To go back, press ESC.
(The screenshots are from How-To Geek. Please ignore its pop-ups requesting that you add yourself to the site's mailing list.)
The primary user of a Chromebook in developer mode can press Ctrl+D to skip this prompt each time it appears. But someone else who turns on the device is unlikely to know Ctrl+D. Instead, she is likely to follow the prompts ("Press SPACE" then "Press ENTER") without fully understanding the hardship that following them could cause for the device's owner.
This means the device's owner will not be able to trust the device's internal storage for anything. He will have to operate the device with a USB flash drive sticking out of its USB port, so that all user data gets written to external storage, which is less vulnerable to this sort of data loss. He will also need to carry a second USB flash drive containing reinstallation media for Crouton so that he reinstall Crouton should someone wipe it.
How practical is it to ensure the data on your Chromebook doesn't get wiped without losing eligibility for fixes to, say, the screen hinge and power jack?