Case in point : LHC Higgs results - how many detection's vs how many events? How were the detection's determined... The answer is with a large booster [1] I postulate that out of 12 billion random events it would be remarkable if a booster didn't extract 100 or so items that looked similar to a Higgs detection. Well, let's give it 20 years and a new generation of PI's who aren't invested in this and have grad student…
As for throwing all the data away, the article you link to actually does a good job of explaining how this is done: we look at every collision with thousands of sensors before deciding whether to keep it. At this stage there is absolutely no machine learning anyway (just physics knowledge), so be careful blaming machine learning for any missed discoveries.