Refer to Mr Fry. Sad though it is, our language evolves and, for many people, 'less' is a synonym for 'fewer', and they will be understood.
The corruption/evolution of language (for example the attachment of 'loony' to 'left' or the replacement of 'respect' with 'political correctness', or, for that matter, the debasement of the word 'respect' itself) is something I might regret, but have not the defences to resist.