Your missing the point. Most companies that offer schematic and PCB cad software charge a sizable fee for use of that software. ExpressPCB does not charge a fee for use of the software, but in exchange for using their sw you must have your PCB's made by them (That is repayment for using their sw). So now if one were to circumvent the sw, ExpressPCB would lose revenue they expected to make by letting you use their sw. This is a business arraignment, and one is always welcome to purchase a CAD package that outputs Gerber files, and most cost one to five thousand dollars.