In New York, in the early 1990s, there was a spate of serial robberies where muggers specifically targeted young Puerto Rican bus boys walking home late at night (or early morning) after a shift at a restaurant.

Why, you ask? Why did the Gotham thieves target bus boys - as opposed to mailmen or trash collectors or late night revellers or any other array of men and women who might be walking alone in the wee hours in a major metropolitan city?

The answer is cash. Bus boys, walking in their highly recognisable white kitchen scrubs, would probably be pocketing a sizable wad of cash - their share of the nightly tips, which any ethically sound waitress or waiter would have shared out with the support staff.

It got to the point where the NY police department advised many restaurants to instruct their bus boys to change into civilian clothes before walking home.

I often think of those vulnerable boys - with $60 in their trousers lit up like a neon sign reading: Get it here, boys - whenever I'm faced with a demand to take large amounts of cash out of an ATM. (which happens far too often for my liking)

Never mind that I have to pay my son's after school care, in cash, on a weekly basis. This happened two weeks ago:

On my way home from picking up my son from a birthday party, my husband texted me to ask 'if I wouldn't mind stopping by a cash point to take out £600 (!) so he could pay our builders'. (We're having extensive work done on our house at the moment and it's taking a fair amount of Homeland marathons and bottles of Casillero del Diablo to keep me sane.)

Now, although I am no delicate flower, walking home in South London, in the dark, with a child, and £600 in cash - did not fill me with a sense of ease. (I plan on showing our builders the iZettle UK launch videos, very soon).

Many banks, consultancies and providers, stress the importance of 'customer demands' and 'changing customer behaviour'. Now, that's all well and good - but if the merchant, or tradesmen or after school club based in a South London church basement, only accepts cash - your desire for mobile, or contactless, or stickers or whatever is pretty meaningless.

It's not just large cash payments that have been bugging me. My husband has been on at me for weeks to write about the local pub near his work. The pub has a clearly marked contactless-enabled POS terminal at the bar - but refuses to let him buy a pint with his card because "the minimum spend is £5, mate". (my husband is a cheap date)

Just last week, my husband had four black cabs, all with card terminals visible in the back seat, drive off on him because he mentioned he planned to pay with a card. (he wasn't even asking to go south of the river!)

The key to changing payments behaviour does not lie with customers - it lies at the point of sale. Merchants need to be a bigger part of the process through education and favourable monetary incentives.

So, my questions are this:

• When have you *had* to pay by cash when you really didn't want to?
• Have you ever *walked* away from a purchase because the merchant would only accept cash? (a purchase that had consequences like, your bathroom remained un-tiled, your child was left to roam free in the wilds of Lewisham, you walked to the train station with heavy bags etc...?)
• How many times have you seen small, independent traders, taxis, or tradesmen accept card (or mobile) payments? 

No need to send answers on a postcard...comments are allowed below :-)