[ck2]

It's not a matter of logic.

When there is one cashier and a dozen customers waiting, that tells me the store is too cheap or too mismanaged to have other cashiers scheduled.

The best thing a store can do for customer relations is to open additional registers when too many customers are waiting, it implies the customer's time is important.

I also enjoy discovering it was the store manager themselves running the extra register - it means they stay in touch with how things are done (and how hard the cashiers have to work).

[philwelch]

Yes, but that's not the point. How do you allocate the extra cashiers? Do they just take customers one by one from the existing queue, or do they split the queue awkwardly and encourage customers to form additional queues?

[gujk]

Parent point is that once you have a nontrivial queue, very already lost, so it doesn't matter which style is faster.