But to some players, the fun in role-playing isn't about the story or the characters' personalities, but it is min-maxing stats, creating the most powerful character possible within the confines of the rule system, and exploiting loop-holes in the rules. I have played in campaigns and run a few, where some of my players are engineers and computer programmers, and the highest factor of enjoyment for them is the rigidly defined world bound by the ruleset. (Not all engineers are this way, of course, it just happens that all of my rules-lawyers have happened to be these sorts of people).
I sat in a game of Champions (not as the GM thank goodness) where two players had a 3 HOUR argument because one of them wanted to turn the other one pink. One guy thought this was a very minor power, while they other argued this was a major transformation, and depending on the ruling it could unravel how either player had constructed his character.
I bring this up merely to say that simply writing off the concern, or just "laying down the law" as the GM, isn't going to solve this in every case. In the above example, this little prank had campaign-shattering consequences. And both players could back up their claims with how they defined the rules. You have to make a ruling as a GM, but if you do too many knee-jerk decisions, it will come back to haunt you.
But I think one thing is clear from reading the initial review that started this thread, and that is: rules lawyers can cause problems for the lazy GM. If the players know that every orc in the group they're facing is exactly the same, they are just a disposable encounter, then they can plan accordingly and use the rules to their advantage. Then they are using the rules to govern the encounter, rather than roleplay what their character would do. However, if you do as SaintNicholas suggests, mix up the encounters a bit, have an Orc Shaman and his devoted servant who is a rogue thrown in with the group, it becomes anything but a normal encounter. Take time as a GM to think, "Why are these orcs here? What precautions have they taken to protect themselves from adventurers wandering around the corner ready to kick-butt-and-take-names?"
If you know you have a rules-lawyer in your group, if you're serious about keeping the game fun for everyone (yourself included), spend some extra time polishing up your encounters. And keep notes on the rules that get sprung on you (that way you can try and use them later on to the NPCs' advantage, not as revenge, but to keep the game balanced).
By the way, nice column.
