To Civil.eng what are you trying to protect ? I have been involved closely with civil design software for over 30 years, having been a state rep for a well known civil package so are you trying to reinvent the wheel to match 30 years of development ?
It really comes down to 3 types of people those that want it free, those prepared to pay, I sold at $9,000 Aus the package, the 3rd the pirates who want everything but dont want to pay. But they get paid for there work.
What price are you putting on your package ? Do you sell 1 at $2500 or sell 50 at $100. At the lower level less likely to get pirated.
Look at the Autodesk apps store most software there is inexpensive so gets purchased.