If you use the submit to a URL scripting page, or Adobe Reader 11 there are no limits since extended reader rights have not been applied to the PDF form.
With Acrobat you can also save the PDF from data to an FDF file and then edit that file as needed.
You could also look at have users using the free Nitro Reader product.
If the PDF form does not have the "Extended Reader Rights" then there is no limit on the number of copies of a form that you can receive. The limit is for PDF forms for which "Extended Reader Rights" have been applied to.
If you client has used a hack to apply "Extended Reader Rights" you might want to consult an attorney on how to deal with this client.