Globaliser,
And you could add that being too precise with the estimates would mean a big loss in airport parking revenue. Profits on those 36 minute stays must offer some of the best space utilisation in the business.
It does surprise me though that some airports (eg BHX) are not so quick on providing more refreshment stands around the arrivals hall. Not to mention an on-airport travel agent, and some screens to advertise the latest flight specials.