Plot hole: The first night the toys spent in the Daycare, when Buzz finds Lotso's band playing in the vending machine, there are no trucks patrolling the hallways, and the monkey does not sound the alarm when he sees that Buzz escaped. However, when Woody comes back later, he finds out that those security measures operate every single night.
Suggested correction: This is explained by the toy telephone that Woody meets when he goes back to Sunnyside. The security measures were not as tight before, but when they captured Buzz, the phone tells Woody that they have cracked down on security and that he got lucky the first time.