So I go through the process, push in the card, choose a language, what sort of transaction, how much etc. Eventually a screen message comes up that reads something like 300€ will cost you £245 in Sterling including commissions and fees. Do you wish to proceed? The obvious answer is "yes", of course I wish to proceed. If I were to say "no" the implication is that the transaction would be cancelled. Nonetheless the better answer is "no".
When you answer "no" the transaction continues anyway and the conversion between Pounds and Euros works in your favour because you buy rather than sell or is it the other way around? And we are not talking pennies here. The average rate offered on the screen is around £245 to buy 300€ but the actual cost has averaged out at around £237 when I have answered "no". That's eight quid a pop in the bank's favour.
If I didn't know that banks were honourable and upstanding institutions constantly striving to improve services for their customers I'd be ready to classify this as a bit of a dirty trick designed to confuse people exchanging money abroad.