[Klonoar]

Again, this doesn't necessarily apply in the case of a sufficiently used service like Signal:

- Alice sends message to Bob at 12:01PM - Bob receives generic "check me" notification at 12:02PM

The key point with line #2 is that Bob is not the only user at 12:02PM who received that generic notification, and is likely in more chat than one. Pinning the specific notification to Bob is a needle in a haystack. It's not perfect, but it's not the slam dunk people are making it out to be.

And before that's even a concept, you have to contend with the fact that it's very hard to use an Apple device anonymously. The government doesn't need to correlate message timings, because if they have the APNS token for the device, all they have to do is ask Apple who the hell owns the device.

Anonymity and privacy are two different, albeit related, concepts.

[infotogivenm]

If you have metadata for a couple of messages it is no longer a needle. Not sure what your point about APNS tokens is - I agree, once they hone in on who received the messages Apple would know the device.