I'll try this! I used to use caldav via my mail provider with DAVx5, but I had problems with it not retaining notification settings with recurring events.
I don't know if that's a problem with their caldav server, DAVx5, or my phone's calendar. But worth trying with radicale and see if it works.
There are a few qualifiers here. It's for some users in UK and Australia trying to access sensitive content. And it sounds like it's reaction to laws against youth under 16 accessing social media. In Australia, anyway. So the scope is currently fairly limited.
Should we be worried that this will pave the road for larger privacy abuses? Yes, of course we should. That scenario feels likely, in my opinion.
Is this enough to convince my friends to use a different platform? Not yet.