I live in a place where we pay deposits on bottles, hence everyone returns bottles for the deposit.
Now everyplace has these newfangled machines where you feed the bottles in (one at a time), the machine scans them, and when you're done it prints a slip for $x amount of store credit. (I miss being able to roll up cart up to the minimum-wage bagger and say "I have 75 bottles" and have them just give me the cash, but I'm a Luddite about some of these things )
So, Mr. Dawbs and I went to return bottles while grocery shopping today. There are 6 machines. When we got there,we were the only customers there, so we each grabbed a machine and started putting in our bottles.
Meanwhile, a man and 2 kids arrive, and the kids want to operate the machine (obviously. If I were 6 or 8 and barely able to reach it, I'd want to operate the machine too

), he's keeping an eye on the kids (who are dutifully and slowly scanning their bottles...), and the family takes 3 of the other machines (I'm quite certain dad took his own machine because he can scan bottles much faster than his kids).
So now, with one open machine, suddenly 1/2 dozen people appear to return bottles. Mr. Dawbs "cashed out" his machine and moved to my machine, so we wouldn't be using 2.
So he asked when we were leaving, if that was the "polite" thing to do. We would have been out of the entire return area and off both machines faster (it's slower to just use one, because even w/ 2 people, the machine only takes 1 bottle every so many seconds) if we would have both continued at our respective machines...but by moving to my machine, only 1 was taken for the duration, so the next person in line could get started.
Sooo...are we supposed to use 1 or use 2?