I have an annual membership (it works out cheaper than an Annual Pass). I have had trouble using it at AT. I have been in touch and seemingly this is a known technical issue. So be warned, it is possible that the membership may not work at the AT gate or for parking. The staff were friendly enough, but they do make you wait while they go and check your passs - which seems to take quite a while for a 'known issue'. It happens to some, not all.