A Certain Restaurant in Vegas

So, my friend Eyarin and I are headed out of Vegas.  We decide to stop for breakfast at a certain drive-thru restaurant.  It's 10:28am.  We ask the lady if they're still serving breakfast.  She says "Yes, ma'am, we're still serving breakfast".  We say "Great!  We'll have 2 breakfast sandwiches with hash browns and a bottled water an.......".  She interrupts us with "I'm sorry ma'am, we're no longer serving breakfast"!  It was, indeed, 10:30am.  Can they really do that?  Can they stop you mid-order?  Well, we went inside said restaurant and came out with bags full of breakfast foods and an apology from the manager.  What's wrong with people?