Nearly a criminal

I was within a moment of getting arrested this morning. I had my bike serviced, and had to collect it first thing. The missus said I could put it on her credit card, because my finances wouldn't stretch to the many dozens of pounds that the bill came to. She gave me the card and the pin number and I collected my bike and paid for it without any problems. I needed some petrol so pulled into the nearest garage and filled up. I handed over the credit card to the cashier and he swiped it through the machine, and then handed me a bit of paper
'Sign this please.'
Er, I wasn't expecting that, I thought everything was chip and pin these days (pin number scrawled in biro on the palm of my hand in case I forgot it)? I explained that it was actually my wife's card and I would not and could not sign the slip, and said I will use my card to pay instead. Words like 'highly irregular', 'illegal' and most worrying 'police' were said in my direction whilst I hunted in my bag for my card. So I paid on my card and he said
'You said this was your wife's card?'
'Indeed it is, jobsworth type fellow'
'Well the surnames are totally different'.
Ok, 1-0 to you. My wife, in her wisdom, has never changed her documentation into her married name.
He then called his supervisor and asked him. The guy looked at me and said
'Do you have your partner's phone number so we can contact her'.
'I do have my wife's phone number' and proceeded to dig around in my bag again for my phone. He then said
'You look like you have an honest face, I'm sure you are not lying'. Gee thanks pal. He then gave me the card back and said 'You are free to go'. I think he's been watching too many episodes of 'Taggart'.
I hot-tailed it out of there and was really upset, shit man, I could have been in prison.

Then I thought, is it really illegal to use someone else's credit card? I know me and the wife do it all the time and I never considered anything being wrong with it. Ok, in the past when you had to sign for something we never did, but now chip and pin is in, we do. And what about at work? If I need software or a book that's bought online, or have to buy a train ticket I will use the company credit card. So I did some googling and after 20 minutes or so, I couldn't find anywhere that says it's illegal. I'm sure the cuffs will come out if you try and use a card that has been reported stolen, but just to use someone else's card. Nah, guy was full of shit and I am going to stop by the garage on the way home and have it out with him. Stupid cock, gave me a right scare he did.