Except if they don't. It's not at all likely that whatever they say will get back to the candidate, let alone in a legally actionable form.

Well normally you get the offer only then do you give them your references - get knocked back the then you get your layer to get the papers from the section process.

Now Mr HR manager lets say 30k for a compromise agreement shall we and you fire the person that decided to accept the libelous statement for my ex employer - and when do I start :-)