The Case of the Franks - S4-E13
Revealing mistake: When the limo pulls up to the hot dog stand, Julie steps out from the back seat. And as she walks toward Frank standing in front of the picnic tables, the limo driver is visible behind the wheel. Julie joins Frank at a table, and then Ryan decides to enjoy a last spin in the limo telling Taylor they've rented it for 2 more hours. In the next shot they are sitting in the front seat talking while Ryan is at the wheel, when the limo driver never left the vehicle. (00:41:20 - 00:42:46)
Answer: She is referring the episode entitled: The Best Chrismukkah Ever, episode 13, season 1. She goes out christmas shopping with Ryan and gets stopped by a security when she is out by Ryan's car. He asks to look inside her bag and finds a stolen watch and some other stolen things.