[ragall]

The RFC says a SHOULD is to be treated like a MUST, but well-justified exceptions are allowed.

[Dylan16807]

RFC speak requires you to think for a while about skipping a SHOULD. It doesn't require strong justification.

[pamcake]

When producing a message, it SHOULD have the id. With or withot it is compliant.

On the other end, we may receive messages with or without. Both are valid. We MUST therefore accept both variations.

The second one is a consequence of the former. So yes Google is the violating party.

[HDThoreaun]

No it doesnt lmao. It's quoted all over this thread and clearly is not in any way like a MUST