Avoiding spreading false information because that's leading the community to react quickly.
And if you caught someone spreading that type of info then you have to inform him that he shouldn't do that. As you've said, he needs to validate his information first before spreading it. We know on how quick news are spreaded throughout the web.
But this is something that is really difficult to do in this market, I say this because as we know there are people that are interested to spread FUD because they want to benefit from the panic created by it, this no longer works in bitcoin but it can work in smaller communities, in fact I have seen this in action where FUD was spread and some people began selling their coins for 10% of its current value.