Selling sweets on the bus

We've done two long bus journeys in different directions and on each a boy has got on selling sweets with a formal patter to the passengers. The first one stated with a question - the person who answers it correctly gets a free sweet (the question was what do you call the inside of a duck egg - it doesn;'t work in english because we call them all eggs, but nevermind..) Then the second boy two weeks later, told the exact same patter.  WHY??

Either they are told a set patter by the sweet sellers (proven sales track record Govnor) or they just can't be arsed to change it. and my bet is on the latter. Maybe because we're told to individualise everything, personalise everything that we (I) find it hard to believe someone waiting everyday for 5 hours wouldn't think of trying an alternative joke?? Also in the West we take modification as a sign that we have understood, mastered and progressed, in which case they don't have the same view of progress here (sweet-seller upgrades to drinks-seller shocker?). hmmm sweets..