This is definitely convenient for now, but the shifting browser ecosystem (along with default security changes in Safari and proposed changes in Chrome) is driving the development and adoption of server-side tracking solutions. This is great for the short-term, but I imagine it won't be relevant much longer.
There's a reason why Segment just sold for $3.2 billion... [edited to add: They offer a single integration point and will proxy your data server-side to hundreds of other companies.]
Indeed, I'm getting increasingly skeptical that a technical solution is sufficient to fighting surveillance capitalism. Looking forward to see some serious GDPR fines.
They use CNAME aliasing to make the requests seem like they're coming from your own domain, so you'd have block a specific URL on a site-by-site basis, and there are also fully server-side APIs so you don't even know when data is being captured or shared.
There's a reason why Segment just sold for $3.2 billion... [edited to add: They offer a single integration point and will proxy your data server-side to hundreds of other companies.]