If detentions start getting excessive (more than 3 people every week, the same person in detention every time, etc.) the staff will sit down with Cecil and Maggie and ask for an explanation. If it's determined that the Head Girl or Boy is getting carried away, they may end up getting in trouble themselves, or having their detention-giving powers removed temporarily or permanently.

The same policy applies to prefects, who don't have detention giving powers, but can get in trouble for giving or taking too many points.