The story presented a contrary argument from some admissions officers that I had not thought of. They said Turnitin was a waste of their time and money (about $1,500 for a small grad school, more expensive with more volume) because such plagiarists are unlikely to get past other screens. Someone who needs to punch up his essay with stolen phrases would show inadequate English grades and scores, and produce other signs of dysfunction. They also argue that the process can take up a lot of time.
Who is right? I lean toward the contrarians, as usual, but I can see why the schools want to discourage plagiarism.