안녕, 나나~ ~지 마세요 is more polite than ~지 말아요. It doesn't matter using ~지 마세요 to kids. Somebody bother us that you can say that. For example, my son is jumping on a couch. It looks dangerous. or you don't want the couch is gonna be ruined. 소파에서 뛰지 마세요~ or 소파에서 뛰지 말아요~

Yes, both have same meaning. Although -지 말아요 is commonly used, it is a wrong form of -지 마요. -지 마세요 is honorific form of -지 마요. In the order of politeness -지 마 -지 마요 or -지 말아요(wrong form) -지 마세요 -지 마십시오 The longer is the more polite. They are used when asking, requesting, ordering, or indicating the listener to not do something.