You don't need to host a site. The data format to send data into Google Analytics is an open API (called the Measurement Protocol). You can just ping Google's servers directly with the appropriate payload, which include crafted URL parameters.

The actual google analytics account has a setting admins can control to only allow data from specific domains though this can be faked.

Also, usually these IDs are copied when someone clones a website they want to steal the design of but they don’t bother updating the style or JS.

Any info about what domain is being visited would be client side, which could be easily changed.