I also thought a bit odd, every other router we play with, being our second one ( link a netgear to the HH3), dads or sisters old one used to play with has a log out.
still close all brower windows and works like you noticed. odd way of doing but goes. might update its self one day and they put one on it on the web pages. Or the next version, HH4 I guess if emaginative!.