You can remove the DOMSubtreeModified event listener first, then you are free to modify "locked" content as desired. I hope to not see a day where the Web Inspector lacks proper facilities to inspect and modify a page.
If this trend were to come back I would hope to see it quickly fade away because it'll just become a game of cat and mouse in which ultimately if you want your average user to see the content you have to give them the keys. Hopefully this type of locking becomes a thing of the past like it has before.
In the end the data goes to the user so a way would be found with or without Chrome or any of the other big wigs. What they should do is focus on how to brand it better so users know where it comes from - this would create a way to spread free idea's while giving credit where due and hopefully pushing the idea of the free web further.