Hey OP guess what.... tried to duplicate your test, it don't work. The session ID expires as soon as i logged out. Neither me nor a friend of mine who is an IT/Programer were able to reuse it. As the message was given that that session id is no longer active. As well he tried it while i was logged in to test your second claim. Again the message was given that the ID is currently in use and that he DOES NOT have the rights to use it, yet alone log in while i play. Only thing you prove in your OP is that you happily give out your account info despite it being a bad idea. If you have taken the time to set up you PC security, and SE account security, if anyone who is not on your PC tries to log in... your account should get locked until you unlock it.