for each bread you get a different ID is my understanding of it.
so if you find the same id in a different bread, it's not the same anon (or it could be but there is no way to prove it)
if you have a trip code then one can verify a name associated with it.
that is how we know when Q posts. And also, Q can post with different ID's in the same bread. Or even not with a name and with a name with the same ID.
if Q posts without a trip, and then posts with one, using the same ID, then the rule is that the one without the ID does not get put into the Q posts at the head of the bread.