As a follow-up to another question...
I wrote a commercial, proprietary (bootstrapped) addon that my client currently side-loads to the regular Firefox channel (not developer or nightly).
My understanding based on the Mozdev article is that if I wish my client to be able to continue using the regular Firefox channel, from Firefox 57 onward, that after I've ported it to a webextension I need to have AMO sign my code, even if I'm privately distributing it.
Self-distributed (unlisted) versions
After accepting the Developer Agreement, choose the platforms your add-on supports and upload your add-on file. The file will be scanned by an automatic code validator which will show a number of warnings or errors, depending on what it detects. If no errors are found in your add-on package, your add-on management page will be created and your file will be immediately signed. You'll receive an email with instructions on how to download the signed file.
Q1. Is that correct? Do I really have to trust Mozilla with my source code?
Q2. If I choose to forego signing and have my client use the Nightly/Developer channel, are Mozilla likely to change their policy in the next few years?