If the discovered requirement are not fulfilled or implemented properly then it leads to dissatisfaction of client.
As, In SDLC-2013 requirements are break down into implemented and non-implemented requirements.
The non-implemented requirements are passed to the technical team for the feasibility study of the requirements.
This team also identifies the various risk associated with the requirements so, that the conclusion can be drawn about the implementation of requirements.
If some Non-implemented requirements are not technical possible or feasible then the client is informed about it during the initialed stages (first phase) so that the client does expect the system with fulfilled no feasible requirements.