In the case of USA vs. A Swartz, there were already over a 100 filings and the case had not even gone to trial yet ( http://ia700504.us.archive.org/29/items/gov.uscourts.mad.137... ). All that back and forth requires billable hours from a very pricey attorney, the money adds up very quickly. I do not know enough about the legal system to determine how the discovery/pre-trial motion process could be made more efficient and cheaper for the defendant.