during user testing, it was expected that closing the tab or browser would end the towtruck session (needs discussion)
It does? Well, it doesn't close it cleanly, the session does stop. We could try to send a bye message in onunload. We also don't kick anyone out when you receive a bye message, so the session doesn't end for that reason too. (I think there's another bug related to that part though.)
i think users' wanted to be able to close the tab/browser, and end the session
On further consideration, it's pretty hard to figure out the difference between navigation and a tab close.