Victorianitas

There's a fine line, but I'd draw it at 'rude'. Impolite. Discourteous. A lot of conference behaviour which isn't exactly praiseworthy falls short of that: palming your wedding ring at the registration desk is sleazy, but not really rude; asking eighteen questions along the lines of "Could you say a little more about how your paper intersects with my research topic?" is annoying, but probably unintentional; losing all copies of your paper half an hour before your panel starts is, well, just academia; getting drunk and falling over, in whatever context, is possibly inconvenient for whoever's on clean-up duty but still not rude unless you do it during a panel. (I'm sure this has happened to somebody, somewhere.)

A lot depends on seniority, too. Planting questions in the audience, or with the chair, wouldn't usually count as rude because it's behaviour typical of people at their first few conferences, after which you realise that people usually won't go for the throat during Q&A. Presenting the same paper at consecutive conferences, especially when you know you'll be presenting to roughly the same audience, counts as rude because the worst offenders are the already-established.

The bad behaviour, then, as personally witnessed by me or immediate friends and colleagues:

+ Going over time. Again, this is mostly restricted to the ranks of People Who Should Know Better ("Congratulations! Here's your professorship, your next eighteen monograph contracts, and your loss of ability to count to twenty!"). Forgiveable when it's a few minutes over; less so when it's not only twice the length it should be, but the immediate cause of getting all snippy with the chair who's asking you nicely to wrap it up. I don't want to pass judgment on individual papers, since I've seen great speakers as well as poor ones go over time, but it's worth bearing in mind that your audience will not care what you're saying once they realise you're making them miss lunch.

+ Stamping on the dreams of the next generation. "You're doing a PhD on what? Huh. I find it difficult to believe nobody's done any work on that before." Or: "I suppose they call that cultural studies," said in the verbal tone equivalent of holding something out at arm's length between finger and thumb. Or: anything about the woefulness of the job market these days. We know. Believe us, we know.

+ Writing your paper during somebody else's. You don't need to write your paper months in advance, and you don't need to write a paper so brilliant that no last-minute thoughts can work their way in there, but even if you got so wrapped up in Garfield 2: Paws of Persia on the plane that you couldn't do what everyone else does and write your paper at an elevation of 30,000 feet, you could at least have the decency to pretend you're paying attention during other people's papers. If nothing else, make it look like you're taking notes. (An addition to this: there is no excuse, ever, for making substantial additions and revisions to your paper during somebody else's when you're on the same panel. May all your field's journals take three years to reject your articles, and may all your students plagiarise.)

+ Pretending to be deaf so that the speaker has to repeat "No, I haven't read that" loudly three times during the Q&A. I don't think this one needs further elaboration.

+ Assuming the entire room needs to hear what you have to say, unless, of course, it's something like "Excuse me, but the whiteboard's on fire." Implicit in a lot of conference activity, but only crossing the line into rude when it comes to, say, talking over the panel chair when they're trying to wrap things up, shut you up, or pick someone else to ask a question. Or, when Big Famous Speaker has decreed that she has time for three questions only, grabbing the microphone runner when questioner #3 is talking to demand that you get your chance next and time limits be damned. (Actual exchange when this happened: "Um, maybe you could try to catch [speaker] afterwards?" "It is important that everybody here hears my question.")

+ Turning up for your session only, and then disappearing. Rivalled only by the people who make the organisers' lives a nightmare by demanding all kinds of scheduling adjustments, and then don't turn up at all. This one is always a mixed blessing, because on one hand it's not like you're going to miss them much, but on the other hand oh for God's sake.

But! To be positive. Academia has its own little mutations of politeness, as well as the Bad Behaviour outlined above. My favourite story, about a certain big-name philosopher, involves a brilliant solution to the problem of how to applaud when you're holding a full wine glass in one hand and there's no nearby surfaces: she clapped just as loudly as everybody else, wine glass balanced perfectly on the top of her head.