I agree that it is important to have a good plan of how to handle testing failures when doing your V&V, but I like the points that @gh56, @merzkrashed, and @Sanam brought up, about spending more time on coming up with a reasonable and appropriate value for the acceptance criteria to reduce the risk of having failures during V&V. This definitely will not eliminate the possibility of having failures, but I think it will definitely reduce the possibility for failure. In projects I have worked on, I have seen it happen often where acceptance criteria for a test is taken from a previous project or some predicate product, the device then fails in testing, and an investigation into the failure reveals that the acceptance criteria was not really applicable or reasonable, which then means the team must agree on a new acceptance criteria. This is a long process that I believe can often be avoided if you put in a little more work defining your requirements, so I agree that spending a little more time defining your testing acceptance criteria can save you a lot of time in the long run.