I made a similar snippet of JS code earlier today (never got around to posting it). It's pure JS and only a few lines that devs can add to their sites. Feel free to use or modify it as needed: https://gist.github.com/matthewdfuller/69f990f58f1e0850443e

I would place it on my websites but at least make the warning message centered horizontally and vertically. Give it a background color, a border, something.

Remember the SOPA banner that was widespread and easily gave across the message? Aim for something like that.

If you organise a world wide protest using this I definitely think it would spread the message.