Every week a Guardian Money reader submits a question, and it’s up to you to help him or her out – a selection of the best answers will appear in next Saturday’s paper.

While in the airport last week I went online and purchased something over my smartphone. My partner said I was mad because I was using the airport’s open-access wifi. Is it really that dangerous? Can crooks get your card details that easily? Should I now cancel my card?

Do you have a problem readers could solve? Email your suggestions to money@theguardian.com or write to us at Money, the Guardian, Kings Place, 90 York Way, London N1 9GU.