>Thanks but...
>
>Does using their tables violate copyright? <- That's the key question

Michael,
sorry about that ::(.
This is a question to lawyer? and the result is a waist of money and time.
Copyright law differs from country to country so there will be no straight answer.

In the end the data belongs to the client. This all you can deal with. If you read the data as I suggested or force the client to do it (even under your supervision) you get the data to import it into a new structure. This will keep the data alive (what is your customers concern is'nt it?) and you come out of that trouble.
I have never seen a client using my programs using plain tables (what would be the other reason to keep the old structure).

Agnes