Hey xShadowx...yes, I have seen this in US parks...specifically the Six Flags parks. In many cases its not a full shop front, but vending machines (as some others have mentioned), or I have even seen vendors with a tray or bags selling stuff on hot days in the queue (like a vendor at a ballgame)...and they sell out really fast when they are there. A constant stream of vendors coming in with new stuff. So, the idea of guests getting thirsty while in line is not that far from the truth (not that I fully believe this was programmed in the game specifically). As some others have mentioned as well...drinking fountains could also be a big plus and easy to fit in a queue without much redesign to accommodate them. This is very common in parks I have been through.