[snek]

I want to start out by saying that I use coinhive on my own site.

I think its important to notify the user that you are doing things without their explicit knowledge. Technically you are taking advantage of their system for your own monetary gain, and in fact they spend more generating that money than you receive from their efforts (by averaged data from comed's 2016 demographic census).

"When a visitor visits a website, is there an implicit agreement to expend resources to load all of the website?" I don't think that mining cryptocurrency counts as part of "loading all of the website," and I would go so far as to call that extraneous.

Cookies are actually not notified only for their privacy implications but for the fact that they store data on your device.

As a user of any website, I am fine with coinhive running as long as I am aware of it. Checking the network waterfall to see if assets from coinhive were loaded is a bad experience to check if the page might be doing something more malicious. All in all I think we end up where we began. Be kind to your users, since they are, of course, who you are catering your experience to.