Are all Class Members forced to participate in the class action?

Typically, no. During the course of the litigation all potential members of the class are generally provided with notice of the lawsuit and given a chance to “opt out” of the class. If a potential member of the class opts out this means they can decide whether to pursue their own individual remedy or action against the defendant if they so choose.

However, if a potential class member does not opt out then they become a member of the class and are bound to the decision or conclusion of the class action, once the class action has been certified, including sharing in any recovered obtained by the class.

[Source: SFMSLaw.com]