Jackie ... Airlines/Tour Operators can face penalties and the expense of flying someone home immediately, if the passenger is discovered by immigration officials to have a passport which does not have the minimum legal validity period for entry to that country. To try and avoid placing themselves in such a position, that may well be one reason why some areas of the travel industry impose a minimum passport validity requirement for all countries, even in cases where no such immigration requirement exists.
It some cases it seems very unfair, but in others cases you can see the logic.
Just now for example, we have a long running saga in our Greece forum where many of our members were booked into a new holiday complex which has not been completed on schedule and which was pulled by the tour operator on Friday, just hours before some holidaymakers were due to set off. Those members may have passports which comply with immigration requirements for entry into Greece, but if that tour operator was to urgently try and secure holidays for those members in alternative resorts and countries, the choice may be restricted if their passports do not comply with immigration requirements for those alternative countries.
It is a difficult and problematic situation because most holidaymakers tend to check out individual immigration requirements for the specific countries which they are visiting, rather than any blanket policy imposed by their tour operator which applies to all countries.
But one of the main problems appears to be that there is little or no flexibility in tour operator policy. If someone presents himself at check-in for a 2 week holiday, with a passport valid only for a further 6 weeks, airline staff should quite rightly deny boarding if there is an official immigration requirement in the destination country which specifies a minimum passport validity period. But where there is no such immigration requirement and passports need to be valid only for the duration of stay in the destination country, then airline/tour operator staff should have the discretion to waive company policy on the issue.
David