It basically says that it requires staff attention for another reason, is it really necessary to notify all the staff just to handle a duplicate. I’m thinking spam is the better candidate but it’s not really advertising or vandalism either. Unless a new option for duplicates was introduced, as it’s a common issue.
Please use flags without hesitation if you think something is wrong with a topic. You don’t have to worry about annoying staff by notifying them – it’s their job to handle the flags and they happily take care of these issues.
All flag options are the same: the ones apart from “Something Else” just have a default message attached. (so effectively, marking something as “Off-Topic” is the same as doing “Something Else” with message “Off-Topic”) It doesn’t alert different or fewer/more staff members, it’s all the same.
You can use “Something Else” and then write out “Duplicate of <…insert link here…>”.