In the scene where Arnold and Willis are trying to get into the health club but are being pushed out they point out that their dad who is a member, that his name is on the board for the Athlete of the Year "Philip Drummond"
Carl the front desk clerk says "great you can read" however if Carl was observant at all he'd see that only the last name is written down and the first name is in initials P. Drummond in logic and observation if they were making it all up then how did they know the P stood for Phillip.
Note: When Arnold and Willis arrive home from being initially kicked out of the health club, they walk into the penthouse and Kimberly is listening to music. She quickly turns off the stereo when the boys enter and start talking to her. Although no lyrics are heard, it is clearly a few seconds of Prince's new album and title track Controversy.