Yeah, I think the lack of a solid definition for "rules lawyer" does create a lot of the confusion.

Someone posted a link to this article in another thread: http://lookrobot.co.uk/11-ways-bette...-work-version/

Which includes the following quote:

"SIX. Know the system, don’t be a jerk about it.
If you know a system, you are easier to GM for, because you know your character’s limitations. You can calculate the rough odds of a particular action succeeding or failing, just like in real life. You can make prompt assessments of situations and act accordingly, because you understand the rules of the world.
(New players, of course, get a free pass on this one. But do make an effort to learn the rules, obviously, if you’re keen on sticking around in the hobby.)
But for the love of God, don’t rules-lawyer. Do not do that. It is not hard to work out, because here is a simple guide – if you are arguing over a rule for more than twenty seconds, you are a rules lawyer. You are the Health and Safety Inspector of roleplaying games, and you need to stop talking, because you are sucking the fun out of the game.
There are times when the rules are wrong, and that’s fine, but I’m hard-pressed to think of that time the guy remembered the rule and we all laughed and had a great time because he made the GM change it."

Which really got me thinking about the absolute prohibition against rules lawyering. It says not to argue for more than 20 seconds, but as the old saying goes "it takes two to argue," so even if both people agree to drop it after 20 seconds, whose interpretation do you then go with?