recipient that (a) is present for (b) to work, no
matter if it's the
same element conveying it or a different one.
I suppose that's true. The main thing is the problematic
<message>
<body>Some troll statement</body>
<mention occupantid="blah" />
<mention occupantid="blah2" />
<mention occupantid="blah3" />
</message>
Where these users get notified but don't know why. This was an early
complaint when I implemented
https://xmpp.org/extensions/xep-0224.html which
I solved by highlighting the message as "this one is to everyone" in the UI.
But when it's not to everyone, and indeed if 99% of the time there will be
your name in the message, it makes more sense to highlight a name then to
add some other UI. At which point you have a dependency on whatever does (a)
anyway and they might as well be together if you need them both...