To be clear, I'm aware there is a difference, I'm just curious how the difference would be stated or determined in something like a debate style argument.

Take the following three statements:

1. "A large majority of people are doing it, therefore it must be right."

2. "A large majority of people are doing it, therefore the odds of them being wrong are small."

3. "A large majority of scientists agree that statement X is valid based on the interpretations of the data collected in research, therefore we should plan ahead assuming that X is correct."

In my opinion #1 is clearly fallacious, but #2 is a little more vague since we are talking more about odds of it being correct, rather than directly stating it is correct due to the majority holding that opinion. #3 though, is generally how scientific knowledge is developed and acted upon, however it still seems someone could argue that it's using the Bandwagon fallacy.