Some one did both to our startup. It was one of the most productive meetings that I had. The conclusion that we needed to shut shop was pretty clear after that meeting. It was something that I guess we knew already, but needed validation (you know how much founders hang on to hope).
So yes, if an idea sucks, say "it sucks." It will be a revelation.
So yes, if an idea sucks, say "it sucks." It will be a revelation.