If you want to take the risk and are holding confirmed reservations for the segments you will not fly, do cancel the reservations (without announcing to the agent what your real plans are).

As the previous poster observed, OW's recourse is to charge you or your TA the unrestricted point to point fares for the segments you did fly - a sum that if collected would allow them to offer salted peanuts to their pax on a LOT of flights. Although no one has ever heard of it happening, if you find yourself having become the poster child, it will be too late to do anything but pay, beg for mercy, or litigate.