I used to work at a fast food place and we (the employees) were required to ask if substituting Pepsi for Coke was okay because the Pepsi and Coke companies are so competitive. Also, some customers would get extremely angry if they weren't asked. One time, a guy was so mad that he took the lid off his drink and tried to douse me with it through the drive thru window! Luckily he missed. I wasn't even the one who forgot to ask him if a Pepsi was alright because I was just the cashier that day and not taking the orders. For some reason I ended up having to clean up the mess though. Some people... less