Is this right? thanks

band wagon appeal

Explanation:

This is a social heuristic defined as an accelerating tendency for more and more people to adhere to a group's behavior when they realize that this behavior will satisfy their interests and will make the group accept that person more easily . Another definition is the diffusion of a pattern of behavior across a group or population.

An example would be a situation where soldiers during a revolution or civil war decide to defect to the rebel faction because many others have also done so.