Support leading & trailing spaces in node names and paths

Through Session.move(), I've tried to change the name of a node, adding a leading space character.
For example, from "/root/child/name.jpg" to "/root/child/ name.jpg".
The call to Session.move() and Session.save() didn't throw any error but the end result was a no-op: the node name hasn't changed.
On the contrary, moving from "/root/child/name.jpg" to "/root/child/_name.jpg" worked fine.
Is the (leading) space character invalid in a node name?
Or is there any peculiarity in JCR / ModeShape that I'm not aware of?
Thanks.