We go through this every time there is a DARPA challenge:
5 Intellectual Property
DARPA claims no rights to software developed by Open Track competitors as a result of participation in the CGC. DARPA does not intend to disclose the CQE and CFE Technical Papers outside the Government, with the following exception: CGC Technical Papers may be handled by DARPA support contractors for administrative purposes and/or to assist with technical evaluation. All DARPA support contractors performing this role are bound by nondisclosure agreements. DARPA does not intend to disclose CGC Technical Papers to contractors to duplicate, commercialize, or for reprocurement or reverse engineering purposes.
Do you think all the participants of the past DARPA grand challenges relating to autonomous vehicles have given away their IP? Of course not. Those teams that pushed through have made lucrative deals with car manufacturers and others.
All DARPA want's to do is spur innovation. A challenge like this is essentially a heads up that in 5 years they'd like to spend a lot of money on procuring services like these. In the past, they'd just give someone the money to build it, and maybe it worked, maybe it didn't. At least now it's a bit more market driven.