Do you know how many people check in every single time they work out?
People don’t use Google Maps when they know where they are going, but they will check in.
As far as adblockers blocking contents “in the DOM”, that doesn’t help if you’re using the FB app - one of the most popular apps in the store and most people aren’t going to install network based ad blockers.
Only geeks use Google’s DNS. Most people use whatever DNS the DHCP settings on thier router tell them. If you are using cellular data can you even change your DNS?