In Parfum Palace, there is a wandering minstrel who will sing a little song. You then have the option of tipping him. The same thing happened with the man who was telling me about how the Battle Chateau works. Is there any point to tipping people?
As far as I know, the tips only contribute to a medal in PGL (Pokemon Global Link, if you sync'd your game with your Pokemon Global Link account):
And when you click on the link...
I don't know the exact threshold to get the medal nor I know if there are any more effects, but currently, I don't think there are any effects besides getting the badge.