Hertsmusic, for one, was surprised to discover that it would not necessarily be protected if one of the musical instruments it delivered to customers through the mail fell into the wrong hands.
'We were always under the impression that if we obtained authorisation, we were guaranteed the money,' said Ian Harrison, managing director of the Watford-based musical instrument retailer. He was put right by a leaflet sent to companies dealing in mail-order or telephone sales by Barclays Merchant Service.
'Realistically, there's no way of completely securing yourself against charge-the letter said.
However, it suggested ways of minimising risks at the same time as reaping the benefits of extra business that can be provided by accepting payment by card.
Among the tips: never release goods to taxi-drivers or others calling personally; ensure that you obtain the card number, expiry date and full address; check that the card is not subject to a warning notice; and, if possible, obtain a signed and dated certificate of delivery.
A Barclays spokeswoman said that the move had been prompted by a rise in fraud of this type. Although the proportion of credit card fraud in the mail-order sector was small, the problem was one of which retailers needed to be aware.
The entry of virtually all banks into the card-processing field has brought prices down but means that individual banks are able to verify the bona fides of their own customers only. The Plastic Fraud Prevention Forum has been established to address this issue.
Meanwhile, Mr Harrison and others may be reluctant to entrust their goods to the post. Hertsmusic, which has been trading for 14 years, says it will seek extra mail- order business 'with extreme trepidation'.