So in my area the 40k fightclub is present at every tournament, except for those are Merlyns, I am usually the only fight club member there and it usually falls on me to represent the club at those events. Since the fightclub has such a presence in this area it's core ideals have become ingrained into tournament organizers standards. As such sportmanship, the club's pride ideal, is a huge factor in most tournaments in this area. Meaning that if people don't like your lists for being too "Cheesy" (that's the local term for powergaming your list) or you have a bad attitude or even if you are a RAW (rules as written, as apposed to as intended) player you have a good chance of taking heavy hits on your score and not winning anything.
That's why I take a different approach. For one I try and write fun lists that focus on synergy as apposed to efficiency. That way people don't see double lash and immediately mark me down. I have always been told that I am just a nice person in general so having a bad attitude is never a problem for me. Rules interpretation is where I usually take the hit but usually I am winning by enough or losing enough where I can just let things slide when I need to. But sometimes in the right circumstance I can use my superior rules knowledge to my advantage and gain the unforseen loophole not anticipated by GW.
An example of such a tactic is the necron shuffle. In the codex when you succesfully we'll be back roll you are told to place the model in coherency with the unit. (except lords) What it doesn't say is that you must put it anywhere near where the model currently is. So for example my unit of warriors could have taken 5 casualties last turn and I would pull them from the back of my unit. Now say I make 3 we'll ba backs. using the Necron shuffle tactic instead of me just standing them back up and putting them in the back of the unit again I would place them 2" ahead of my front rank. Essentially moving the unit 2.5" (counting the base as approx. 1/2 and inch.) Best part is the unit didn't move. so I can still fire at full range if I need to. A lot of players see this as cheating and alot of the time if I know I am playing a player that frowns upon this kind of playing I will "hold the cheese" as it were and just stand them up where they fell over.
But if I happen to know that my opponent isn't going to mark me down for the tactic I make damn sure to use it if neccesary.
The important thing is making sure that I feel out the situation and know when the time is right to do it.
That's it for now. Next time I think I'm going to write up my list for Spocon, I want to take something competitive yet fairly friendly and very fluffy so joing me next time when I talk of the Children of Avarice.