Jon's right. If you don't get the clippings off, they are going to rot down, make the soil more fertile, and thus your rough will come back thicker and more meadowy than ever. The same problem arises when, on a new project, people sow the rough areas too densely in order to get a nice looking stand for opening day. Then you have to thin it out - which is a difficult, time consuming process. And perhaps the single biggest problem - I'm sure this was an issue at Trump - is irrigation throw falling onto rough areas that ideally shouldn't get any additional water. On a windy site, it's unavoidable. But it means the thickest rough is right next to the play areas - not good.