I'm not sure the title makes sense - I learned why having 4 founders can be ok, but that doesn't mean the 2-3 founders advice is bad - just that you should have a reason why you think you won't run into problems. It seems too specific to be about recognizing bad advice, just that a traditional rule doesn't always apply (and how many rules always apply in business?)
I don't know how to certainly recognize good advice but some are certainly bad: If someone doesn't ask you any question on your business and doesn't know you well, he probably give you a bad/unsuitable/irrelevant piece of advice.
To me the moral of this story is that advice is just that, advice. There are always exceptions to every rule.