In August of this year we booked to go to America for two weeks. We booked with United Airlines and paid the deposit of �500.00, we have now found out one of the party has convictions and would not be allowed into the country. We therefore cancelled but was told we had lost our deposit, we don't fly until April 07 and at no time were we told by the Travel agent or the United Airlines agent about these rules. Do we qualify for all or part of the deposit?
Assuming you have a non-refundable ticket and your contract is with the Airline, not the Agent, I don't think there's much you can do. Its up to the traveller to establish the required documentation / constraints unfortunately. The long length of time until travel doesn't come into it on a non-refundable ticket.
The person with convictions could always apply to the American Embassy for a visa. They would not get into the US on the visa -waiver programme but they may be able to get a visa.