Current GTM, configured (via the server UI) to inject tracker X:
gtm javascript loads, pulls down the config, injects tracker X javascript into the browser
new gtm:
gtm javascript loads, pulls down config, streams events to google servers to fan out to tracker X as configured
So blocking gtm.js off tagmanager.google.com / www.googletagmanager.com / the various other domains still blocks all gtm injected tags.
The tl;dr is they're become much closer to segment -- which does the data fanout internally to segment. But they should still be straightforward to block.
gtm javascript loads, pulls down the config, injects tracker X javascript into the browser
new gtm:
gtm javascript loads, pulls down config, streams events to google servers to fan out to tracker X as configured
So blocking gtm.js off tagmanager.google.com / www.googletagmanager.com / the various other domains still blocks all gtm injected tags.
The tl;dr is they're become much closer to segment -- which does the data fanout internally to segment. But they should still be straightforward to block.