Cool concept, but morally dubious. You're basically using people's electricity in the background without people knowing, not unlike bitcoin miner malware.
https://ss.crowdprocess.com/opt-out.html
Having said that, I am the first to admit that many websites aren't currently displaying this, we need to work on that.
Or you could even just provide website owners with a "global opt-out" URL that they can stick in their footer.
We don't want anyone on the platform who isn't aware/comfortable with it. Our instructions to the websites (when they join) are to create a link to the opt out page. I supposed it could be a direct opt out
What's your opt-rate rate so far out of the sites that have shown this option?
do you have any real data regarding hidden cost to a site visitor? like power consumption A/B testing or something?
A standard for how to display might be called for, perhaps?