The word of the law vs. the spirit of the law. Whenever people get together to play a game of any type they have to decide where on that spectrum their game play experience will lie. Most cooperative and/or casual games will lean towards the latter, but most competitive games sit bunched around the former.
Each gamer has their own opinions on the philosophy of game design, and I’m no different. In my mind, if a game is designed to be played in a competitive format, then it should be designed to abide by the letter of the law. By designing for the more strict guideline, those who prefer the more casual and/or want to tweak their experience – to make the rules feel more fluffy or appropriate to their own vision of the game – can do so. Designing from the opposite standpoint results in a game that works for those on the spirit end of the spectrum but will likely negatively affect the word end of the spectrum, as the rules will either fail to accommodate certain interactions or maybe even resolve them in a manner the game designers didn’t desire.
Privateer Press seems to take the word-emphasized view of design, which I certainly appreciate. Each incarnation of their Steamroller tournament system has had its flaws, but for the most part they design their game and format so that it can be played in a highly competitive venue and not break down to dicing-off rules interpretations. In the past they’ve even made rulings that seem to go counter to how a rule was meant to be played when it preserved the word of the rule. For example, the ruling on MkI Vilmon that allowed him to run and still use his Impervious Wall ability. The rules supported the tactic, so whether or not it was intended it was supported (until the rule was reworded in MkII).