ninwa, from all the business lessons I've spent hearing my teacher brag I've come to a definite conclusion that there were no commitments. Then again, this is only my teacher so I'm not going to definitely claim that all teachers are like this, although I am going to assume that all teachers who plan far in advance don't have an urgent reason to travel overseas.
I'm all FOR if a teacher has a legitimate reason to vanish overseas e.g family problems, sick family members, crisis situations, but not for the sake of just leaving for enjoyment. Teachers have 12 weeks holidays to go and do that. If its not summer in their desired destination, bad luck, commitments and sacrifices. My sister is a manager and she can't take time off during the summer - commitment to duties.