As has been mentioned a few times, one reason for standing back is the situation in which there are two or more registers, and a single line exists for all of them. I find this to be the most efficient sort of line, as you don’t have to waffle that your line is faster/slower, longer/shorter than the next one over, and you don’t get burned by the person in “your” line that takes an inordinate amount of time at the register. Multiple registers for one line of customers provides a nice failsafe for this. Unfortunately, there are stores and situations where this is the common practice, but there’s not a roped-off single line to show that it’s one line feeding all registers. It’s an open expanse. Stand too close, and you commit yourself to a particular register as the next customer there. Stand too far back (especially if you’re the only person waiting) and somebody will mistake you for not being in line at all.
I feel the best solution is to have two registers for each one line, and have it clear that it is the case. That way there is a safety valve for slow registers, but there is also enough of an established line culture to discourage cutters. This is the way it worked in a movie theater I did concessions for. There were regularly spaced soda machines, and a register on each side of each soda machine. The lines formed in front of the soda, and branched off to the next-available of those two registers. For three or so soda machines.
Remarkable how long one can write on something so trivial.
<<blush>> Well, sometimes I stand quite a way back from the “main line” because of vision problems. Given the old tri-focals, I have to cock my head just right to read the menu posted above the cashiers. The vision field is better if I’m a ways away. I do try to notice if people show up behind me, and let them know I’m in line or that they should go ahead of me, depending on my mood and how close I am to a decision. Anyway, it’s a possible reason.
I think I cut in on an elderly woman in the pharmacy line yesterday, actually. She was hovering around while another elderly woman was checking out a cart full of non-pharmacy stuff there in addition to her prescriptions, and was just looking at stuff on the shelves, so I assumed that from her behavior, she was waiting for her friend. I stationed myself a few feet back from the woman who was having her purchases rung up, and waited another 2-3 minutes while this was finished, then the woman paid, then hunted for her receipt and asked if the pharmacy assistant was sure it was in one of her bags. I didn’t see any movement from this other woman to get into the line, or to correct my assumption that she wasn’t in line, but soon after I left I saw her move up to the counter. I don’t have a problem in being corrected that I’m not next, but if I did cut in (rather than her deciding later to stop browsing and get in line, for instance), I’d appreciate a hint.
(It was only after walking away from the counter that I noticed I’d bought an interesting combination - oral contraceptives, and a bottle of Astroglide that I’d snagged off an adjacent shelf while waiting. Add one oddball item to that, and the possibilities for cashier confusion are limitless.)
Once at the same pharmacy, I had a woman sidle right up next to me while I was at the pickup counter and get her prescription. (There was a short wait while a register reset or something, so I had mine but couldn’t purchase it yet. I’d already been asked if I had questions, so I guess the staff didn’t see an issue with it.) I heard her make some kind of sound, and glanced out of the corner of my eye at her prescription bag. They don’t put the medication on the outer part of the label they attach to the bag (it’s folded under), but the price is printed in bold lettering. Hers was over $100; mine was $7.50. Lack of privacy goes both ways in that case!
If I’m at an ATM or pharmacy line, I’ll leave about 3-4’ of space, or more depending on the layout of the area. In a regular line, around 2’ I’d say. If I’m 10’ back, I’m either at the end of a marked-off rope that says "wait here for next available cashier/teller’ or I’m trying to figure out what the hell I want and I’m not in line (and will tell people lining up behind me that, assuming I notice them).
