Don A. has a good point. I'm afraid I assumed the solicitation period was over with. If not, then the offeror should formally request the requirement be, at a minimum - clarifiied, or removed. I guess there are other factors to consider here too - is this federally funded and needs to follow the FAR? If not, you can request any of the documentation be provided in a certain format in an RFP and consider it a material defect if it's not submitted in that format. In a previous agency I worked for, if they did not use the language in the supplied sample bid bond, their bids were rejected. (federal funds, non-FAR).
Vern is correct - I don't read that sentence the way he does, but if there are two ways to read anything, an ambiguity arises and it should be clarified.
Also, I understand that some agencies have stopped accepting cashier's checks because they have received fraudulent ones. Those offerors obviously are taking no risk. Perhaps that is why the Agency in Italy will not accept them. They are good - if they are "good". But until you go to cash one, you may not know whether it's a real one or not.
This conversation may not be helpful to the originator, but it certainly has exercised MY mind!