There are a lot of things in 'the Sport of Fitness' that can suck, but few things suck more than getting No-Repped, especially when it really matters (e.g. the Open). Over the past few years the level of competition has gotten so fierce that 1 or 2 reps can be the difference between qualifying and being eliminated.
Now, the majority 'no reps' are not case of intentional cheating, but rather an accidental failure to meet the specified movement standards simply because athletes are trying to go as fast as they can. There is no 'fool-proof' method for avoiding a no-rep; however, by making sure you ALWAYS practice with good form you can greatly reduce your chances of getting 'no-repped' when the pressure is on.
Check out this awesome Infographic from BoxLife about the Kettle-bell swing, what counts, and what is considered a bad rep, so that you can be as prepared as possible when competition day hits.