Why Lie about it

Okay a minor rant here....

This is currently the tail end of the instructing staff and resort super busy time. Holidays tend to bring out lots of people looking for lessons on their new gear, or just because they're visiting family/friends. I was booked out for the entire day between reservations and requests, which in itself is highly unusual for our school.

My 1pm session began with a mother and young male child walking over to me, about age 7. They were to be my next class. After introductions were done, mom pulled me away to talk to me. She informed me that her son just had a complete temper tantrum and meltdown in the lunch room and he was not at all interested in skiing. She wished me good luck and then left.

Working with this young boy, I was able to cheer him up, motivate him and get him skiing. When mom stopped by at the end of the class, we were just coming up the rope tow at which point he yelled out "Mom can I keep skiing?" He didn't really wait for an answer and started down the hill regardless of what mom would have said. I walked over to her to tell her what we'd been working on, how to help him progress, and really what motivated him. She thanked me a lot and ran off to pick her son up as he arrived up the rope tow again.

Two lessons later, I'm working with a different student when angry-child's mom comes up to me and says she left a tip for me in the school. I thank her, and she says a few more words resulting in myself needing to stop the chat as I was teaching. Arriving in the school, the office staff said no one had come in to leave a tip for me today, and there weren't any on the credit card charges seen. We looked around all day but found none.

I have to ask, why lie about it?