Comment 2 for bug 1791363

We do actually have a bolded note in the docs for this! But it isn't in the version in Bionic.

It reads:

     **Note:** This will not work reliably for devices matched by name
     only, due to interactions with device renaming in udev. Match
     devices by MAC when setting MTU.

Do you think that's sufficient?

I will still look into better validation, but it will take me a while to get to it.