What's to stop a website gradually querying different API data on each page load to build up a profile with the same amount of information as before? Will brows

What's to stop a website gradually querying different API data on each page load to build up a profile with the same amount of information as before? Will browsers only allow the first N API accesses forever more? Oh, interesting... lots of nasty mistakes can be made by websites picking a bad set of APIs early on. However it works, I don't trust it if it's coming from Google. I'll keep my multiple layers of ad blockers enabled.