I find it rather disappointing that STN should decide to ban overnight sleepers. Those with good incomes or living in London have transport options for early morning departures / late night arrivals. Plenty of people need to fly for one reason or other cannot afford the extra cost of a hotel or a taxi in the middle of the night (when cabbies charge higher fares). Sleeping in airports is not comfortable and many do it for lack of other affordable options.
There was a tradition that if sleepers were quiet, unobstructive, caused no trouble and could show evidence of a ticket for yesterday / tomorrow on demand to prove they were not simply homeless people sleeping in the airport regularly, then a blind eye was turned.
This morning i had to travel from a remote village to an airport to catch a flight. The only suitable bus left at 3:30 am to reach the airport at 5:15 am, for a 10 am flight. The local taxi firm wanted 150 euros versus 15 euros on the bus. I was very glad to find somewhere in a quiet corner to snooze until 7 am without being woken up.