So BoLS posted this article a few days ago. It is on the Art of Cheating.
BoLS Cheating Article
Why would you actively encourage this? Why would you post tips and tactics to cheat? This should never have even been put on the internet, especially by such a well reviewed well read hobby blog. There are readers there that go to that site to learn what they should do to be better at 40k, and what is presented to them? How to cheat.
So lesson one in being a fair sportsmen: Doing nothing recommended in that BoLS post.
See that picture right up there. Those guys are fair sportsmen. The Olympic ideal. We, as a society are ashamed and disappointed when we learn that athletes like those men cheat. It shouldn't be any different at any level of society.
Lesson two: No one likes cheaters.
Schools, Organizations, Government Jobs, etc. etc. all have Honour Agreements or Challenges. Every university has an academic integrity review board. Why? Because cheating is unacceptable. Why? Because a doing well through cheating proves nothing about the activity at hand. The only thing it shows is that you are proficient in being underhanded.
Basically, you weren't good enough at 40k to win. So you cheat. But that win still doesn't mean you were good at 40k. It only means you are good at avoiding 40k. So how can you truly appreciate what you earned.
I am going to take an example from Starship Troopers by Robert Heinlein. You run a race and get 3rd place. But I give you the medal for 1st. But you know you got 3rd. That 1st place medal is worth moot to you because it represents something you did not earn.
Lesson three: a false victory is an empty victory. You earn nothing, you prove nothing.
This leads to another thing: the other player. He now thinks you are/may be a better player or his army is deficient. This though is unproven. He was not given a fair chance to earn a victory.
So lesson four: consider the other player. Always keep in mind he is here to try and have fun and win as well. Give them that opportunity and don't just take it from them.
Another thing to consider, wouldn't you be angry if some one say, rigged a deck of cards when playing poker. Same goes for 40k. No one, not even cheaters, like to be cheated. So why do that to some one else. And in doing it to some one else you may create another cheater and propagate the problem. Who knows, that propagation may come back when some one cheats on you.
Lesson five: the Golden Rule. Do unto others as you would have them do unto you. You don't want to be cheated SO DON'T CHEAT!
I guess the biggest problem I had with the BoLS post is that they didn't frame it in how to avoid cheating/cheaters or mock cheaters, but they taught cheating.
Lesson six: Encourage honourable fair play, not underhanded tactics. This hobby is about fun, so foster that core concept at all times.