There is a new UK petition:
"Make all UK Government websites free to access without mobile data charges"
This sounds like a great idea. I like it.
In practice, I don't know how easy it would be for a mobile operator to zero rate resources on shared hosting environments (CDNs, AWS, etc).
The ICO, for example, has a link on its website to YouTube (which is certain A Decision in itself), on subject access requests. I doubt an ISP would want to zero-rate YouTube.
@neil Technically, once upon a time you could look at the SNI in the http exchange. Then IPA ICRs started to happen (alongside similar and censorship, in other countries) and the community moved to hide it, first ESNI, now ECH. I won’t be hostage to fortune and say it’s impossible, but if an ISP could do it, the community would move to stop it (again). My views on ICO hosting on YouTube would need a content warning so I’ll make no specific comment on that.