So I used to work at a large grocery store chain here in the Northeast for a few years while in college. We were always busy (#2 store in whole Northeast). I like to work quickly, so I can eliminate my line and just sit back and chill, even if it's for 30 seconds. There were plenty of times where I'd have the shortest line, if any line at all, even if we were busy.
So every grocery store has at least 1 (we had 2) handicapped registers; the lane is wider so wheelchairs, or the mobile store carts can get through. Other than that, they're just a normal register.
I'd say "so this one day", but this happened multiple times, with multiple different customers. The same conversation every time though. It's busy, I'm on the handicapped register, and I've worked through my line and have no customer for a brief moment:
Customer walks by register, stops, stares at me....stares at the register light (which is clearly on and lit up), and then back to me
Customer: Are....are you open?
Me: (gives look of disbelief, looks up at register light).....yeah, I'm open
Customer: I wasn't sure, you have no line!
Me: (looks at light again) I mean, my light is on
Customer: ....Do I have to be handicapped to use this register?
I'd give the most puzzled look every time, you know that look that says "are you seriously asking me this right now?" before telling them, you do not need to be handicapped to come on my line.
I would usually then ask them, how many people I'd be helping everyday if I were to only be helping handicapped customers.
I couldn't believe it the first time it happened. But it happened about a half dozen times
So in case anyone is wondering, able bodied people can use the handicapped lanes :)