Mart, U2 don't overbook deliberately. Most I have ever seen was 3. Think sometimes GDS has when someone has been online at similar times. I took a pax only once from BCN to LPL on a spare crew seat. As the senior crew member,I had to brief him on opening the door in an emergency to which he had to agree. However, at Midland, we overbooked all the time to an extent we were always pulling the business seats from 5 to 6 abreast to accommodate. Resulted in a fifty quid voucher for the pax every time. Sometimes 50 on board. No wonder Midland are no more.