It is a good idea, and my kid did this (as soon as he knew for sure that he wouldn’t be attending each school)
But on the other hand, kids shouldn’t be shamed for hanging on to a WL spot at a coveted school, even if they tell their friends that it is “just to see if they got in.” They do have a right to see the process through to the end. And maybe that student is privately thinking that if they DO get in, they might change their mind and go there.