Ain't.
I couldn't care less. I just used the term "on-line authorisation" because nothing better came into my head. If something else is responsible, so be it. The fact is that most places I use a PIN card there is a long wait-time after I enter the PIN before the till gets around to printing my receipt.
You don't always/often need on-line authorisation when you sign.
The checkout chick supplies the pen, tried and tested. Surfaces are available. Shops are geared up for this, you know.
That can't be true. If it takes a few seconds longer to deal with each customer, it just means the queueing customers have to wait a little longer, they aren't going to be too many of those per till, and if there are, they'll find a shorter queue. And if the queue lengths are too long in the shop, they just open another till by shifting some staff from shelf-stacking to checkout duty until the panic is over and a new panic starts (the shelves get too empty).
If they were that worried about till delays, they'd invest more in staff training so they don't have to waste time identifying non barcoded products. "Is this a swede?" the chap asked me today when handling my turnip [no smutty jokes please]. And then there's having to call for a supervisor to authorise any correcting of mistakes, such as when they ring up x4 for four cans of beer joined at the neck, when it's "sold as fours only" and the "x4" is already implicit in the barcode.