You can't be afraid to be a doubting thomas! Dissent is a necessary part of making thing better, so you can't keep quiet if you see problems in a plan. Nothing is quite as it seems, so anyone who claims to have a cure-all is full of baloney. Ask them a few pointed questions, and you will quickly reveal them to be wrong. A wrong idea is still a wrong idea, no matter how powerful the person who thought it up might be. You'll be doing them a service by pointing out their mistake.