I would say that on wikipedia, no section should imply or contain a question, we should document the comments, questions, and thoughts of individuals commenting on the topic of the page.  I read "Suitability for children" within a subset of "criticisms and controversies" as saying "one of the controversies has been over their suitability for children", not "are Biggles books suitable for children?"  Putting in a question mark by definition asks a question, while leaving it out means the section simply discusses a controversy.  But I'll just log a 3O (and see if I can find any further guidance).   (t) (c) Wikipedia's rules:simple/complex