[grumble about people who:]
"don't say who they are, ask who anybody else is, say what the tune is and sometimes play it so fast that it still isn't clear what the tune is".

Agreed that 1,2 and 4 are a bad idea. Saying what the tune is doesn't happen all that often in sessions I go to, and it doesn't help a lot when somebody does announce that in advance. (In Irish sessions, half the time people won't have a name for it anyway). Announcing the key can be helpful to people who play diatonic instruments, but mainly in a rather negative way ("G minor, forget it") - it doesn't really tell a guitarist enough to make up an accompaniment on the fly.

In a beginners' session where people use sheet music, yes you do have to say what the tune is, and allow five minutes for them to find the damn thing in their unindexed heaps of paper. If they vaguely know the tune, I'd much rather they tried to noodle their way towards it, with all the inevitable mistakes, than do that.