I am unfamiliar with this scheme but it would surprise me if it does not include their hope of persuading people to buy - that is what it is all about. It is up to those who take part as potential customers to sign nothing unless they are in a position to pay and are willing to buy precisely what is being discussed. If they refuse to buy then presumably they are entirely in the right to walk away - make certain you know what you agree to when you accept the invitation. Only rely on what is in writing, never base any decision on anything that is only verbal - it is no good quoting."He said.....".