Comment by CmdrKrool

To some extent, the line between code in the browser core and code in an add-on coming from Mozilla is arbitrary. However, it's a line that Mozilla themselves have drawn. We've been trained to be vigilant when choosing and installing add-ons, to read the list of permissions the add-on is asking for and judge whether we want to take the risk. The implicit messaging to users has been that if you let through a bad add-on that degrades the browser in some way, it's your fault. (Indeed, we're supposed to sympathise with Mozilla when 'badly-written' add-ons slow down the browser and make Mozilla look bad.)

Mozilla have presented "add-ons" as a line where users are supposed to be responsible for what to "trust", over and above the choice to install the browser in the first place. They can expect those users to be watching that line carefully.

(Incidentally, I would still dislike this functionality - moreso even - if it was in the browser core.)