Do you HAVE to glue it together?

[Mooch]

This is a real stupid question, but I'll ask it anyway. Do you HAVE to glue it together? Granted, it won't "migrate" shapes while glued, but does it leak if it's not glued? It already seems pretty tight. It seems that the glue just stiffens the shape. Plus, if it's not glued, then you can take it apart if the roots begin growing down into the piping!
Monty the Mooch