Why Do Convenient Stores Have Locks On Their Doors If They Are Always Open?

Part I of Essay
? At 1:30 in the morning you are driving down Walton Road when you pass the 7-11. You decide to stop in and treat yourself to a nice big slurpee. As you pull in the parking lot you notice that the sign says, "We're open 24 hr's, 7 days a week, 365 days a year." However, ....

Part II of Essay
.... when the store closes they lock the doors and go home. Then, in the morning whoever is going to be opening comes in and unlocks the store and gets it ready for the first customers of the day. This situation would never happen at a store that is open all the time because there always has to be someone working. On a rare occasion, the store might need to the lock the doors if someone outside is causing trouble. However, if they locked the doors and wouldn't let any customers in they would be lying saying that they're open 24 hours a day, ....