What's in a name?

A young Swedish lady who lives in this country had her online application for a Sainsbury's Nectar Card turned down because the computer program wouldn't accept her first name - which is Fanny.  It insisted that she entered "a valid first name".  I suppose Sainsbury's would argue that they are entitled to place what conditions they like on providing a card, but it would be interesting to know how the program has been set up regarding acceptable and non-acceptable names.  There are many people with "unfortunate" first names - Dick for instance (which these days is often a name in its own right, rather than a shortened form of Richard), and not all of them will have the get-out which she had of having a second name which she could use.  Come on Sainsbury's - get a grip!