If you are able to get enough people to do this it would work by definition.
But my guess is that there are too much people involved for this cartell-like market manipulation.
Well they can't do anything if everyone start doing this.
and if someone even dump's thousands of bitcoins , people should not create panic.
we could drive off those dumpers if we would simply buy up what they are selling forcing them to buy back for higher price. But there are some people who thinks about themselves only and join this actions helping to destabilise market which in turn is loss for everybody because it drives merchants away. Think more globally people and not only about your tiny business that is good short term only and only for yourselves.