Rude Words?

As a writer for children I spend a lot of time in the children's section in Waterstones. I like to keep up with new titles and see what is popular at the moment. When I do a book signing, children tell me about books they enjoy. I read a lot of children's books too.
I'm told that children enjoy books with 'rude' words because they make them laugh. Children enjoy anything that seems a bit naughty. Waterstones can easily cover a table with books with wee, poo or fart in the title, just to mention a few. Well, when it's in the title you know what to expect. However, it seems to me that there is a trend these days to throw in a few 'rude' words just for the sake of it. Why? Does the writer think it might help sell more books?
I hope my books may make children smile. I won't be adding 'rude' words just because it seems to be the thing to do these days. I don't believe that it's what all children want.
What do you think?