edi local,
OK, if I accept your premis (which makes me wonder why Swiss airports know a day in advance) then 'on approach' of the arriving aircraft is more than 40 minutes before the departing flight.
The airports are mistaken if they think it gets me to spend, spend, spend in their shops. Let!s face it Duty Free no longer exists and there are NO bargains airside shopping.
Dixons' at LGW quoted me a price for an iPad higer than the apple.co.uk website (which included 20% VAT) when travelling outside the EU.
Airport shops are for suckers.