The machine measures voc's which evaporate at a certain rate. If that rate goes above the legal limit of say 0.8 or something of that nature in 20 seconds then your rubber is deemed illegal. The issue is that boosting is virtually untestable for consistent results. Sure you can look at a rubber and see that the rubbers are curling at the edge of the blade or you could smell the oil used paraffin vs haifu/dianchi and you could tell by that, but it's all subjective as far as tests go. Not to mention that many rubbers are "factory tuned" now a days so that really messes with any testing for paraffin or other oils. This is the issue with trying to figure out whether or not a player is boosting.
Personally it doesn't bother me because it's easy for someone to say that the booster is the reason people are winning, but let's be honest here, training is the key to winning. China has the best training method and thus gets the best results. I've met plenty of Chinese players who switch to tenergy on the forehand and are just as good as when they played with the boosted H3. The H3 made them better players, but since they aren't training regularly anymore they don't want to have to exert themselves as much so Tenergy is an easy substitute because of how much less effort they have to put into the ball.
Personally I'd go as far as saying that booster or no booster doesn't have any affect when you're talking about that large of a difference in skill level. The easiest way to beat someone who is boosting is just to be better than them.
