It will do no good for universities just "to state publicly that there will be no deviation from published arrangements" for top-up fees. Such statements represent "cheap talk" that the universities can later ignore.
A credible commitment such as a contractual promise to give the same discount to all students on a given course, whenever they were given an offer, would make discounting costly in the short term as well as in the long term.
Even then, the University of Poppleton could probably get round such a promise with some discounted courses that are available only in clearing.
Richard Green
Birmingham University