This came about due to a famous tennis coach by the name of Carlos Casely who hosts Tennis Camps for kids for summer vacation. After all the kids are registered for camp, the camp suddenly gets canceled right before it starts because of some unforeseen circumstance and Mr. Casely runs away with all of the money.
So if someone you know collects money for some cause or event and does not follow through and keeps the money...they just pulled a Casely.
"Don't pull a Casely".