I tried looking it up, and most of the information I've found is ambiguous, but it does appear that the actual Boy Scouts of America corporation do, indeed, own the rights to "Boy Scouts". I'm not so sure about "Girl Scouts" though, considering Girl Scouts HAVE been used in fiction before... in the SANFORD AND SON episode "The Camping Trip", a troop of Girl Scouts end up hiking through Fred and Lamont's campsite; likewise in the movie DODGEBALL: A TRUE UNDERDOG STORY, the Average Joes find themselves up against Girl Scouts in competing for qualification into the ADAA (American Dodgeball Association of America).