My flight will be arriving about 11 pm and the tubes close at 11:45. No worries since I cannot check in at my hotel until 8. I am curious to know 2 things. Can I stay at the airport or will they force me thru customs and out of the facility? The second thing is about oyster cards. I was going to purchase one upon arrival but I cannot seem to find anything about the ticket booth hours. Will there be someone there at 5am when the tubes start running again so that I may buy a card?