Malfeasant UI patterns: Google driven "site support" subscription popups

For reasons that are unimportant at this juncture, I found myself clicking about the internet and came upon a site. I read the page (not particularly informative, honestly, and it was not a good site for a first result) and as I scrolled toward the bottom, a non-modal dialog box, in Google colors, very similar to the "hey, do you want to log in to this site using your Google account?" type, except mid-bottom instead of right-bottom, showed up.

Clicking the big blue button, I found, would have signed me up for a monthly subscription of a dollar to "support" that site.

I didn't investigate what would happen if I did click that big blue button, but the defaults looked as though it had by default all the information filled in that the form needed to set up a subscription, it just lacked my permission.

So, uh, if you're logged into the internet using Google, this is a thing that now exists.