I'm looking at a mileage ticket from AMS-AUH and back including the bus service to Dubai. On the return journey, the AUH-AMS flight is early morning. I am not fancying a 04:45h busride and would like to travel with the EY bus to AUH the night before and stay at an airport hotel. For some reason, booking the evening bus service for the same flight the following morning is more expensive than booking bus and flight on the same day. How strict is EY with reserving a spot on the bus or taking it at another time? Can I otherwise just show up the evening before without a (specific) reservation?