I just rejected a suggested edit on this question, where someone had proposed adding homework but making no other changes. Since the question was two and a half years old, I rejected the edit with the 'causes harm' reason and the following detail:
Adding 'homework' tag to this old question will unnecessarily promote it to the front page of the site. Edits to old questions should be substantive.
While homework almost certainly does belong on the question, the edit seemed too minor to be worth the bump to the front page. Was this the right call?
OOPS: Per Melanie's answer, apparently the question already was on the front page and I missed it. Given this, I would have voted 'accept' in this case. The general question stands, though.