Actually, having been in exact same situation myself I can offer the following, Turkey does not have a schengin (spelling maybe?) agreement. It takes about 6weeks plus to get a route approved by Turkey etc. So if you find yourself in Turkey, with an overloaded plane you cannot simply take-off for a nearer airport for a fuel stop, to get that flight plan filed would need that route individually approved(6 weeks plus). So you have a choice, dump the pax and bags and go, or fill up with as much fuel as you can, depart as planned to your flight planned destination and once en-route 'discover' you cannot make it and divert in flight. If you stated to the controller before departure that you intended to divert for fuel he would not let you go. So all in all I think a cheeky way around getting out with all pax and a tech stop without going through the rigmarole of flight planning. Easy to pick up a new flight plan from your tech diversion which is Schengin. Ho Humm. Heavy headwinds don't help either!