The plasma membrane is phase separated into a fluid (Ld) phase and a more ordered (Lo) phase. The latter exists as small “rafts” of specific lipid composition containing a host of signaling proteins. Lipid raft theory links the aggregation of rafts to a signaling event. In its current iteration, the theory is incomplete, as it does not explain how rafts form and how they aggregate and disperse again. These problems are addressed when the membrane is viewed as a critical system. Previous work using giant plasma membrane vesicles (GPMVs) used this framework to explain the dynamics of the rafts. We intended to show critical behavior as a factor for cell signaling. Critical behavior was not easily ascertained and further observations were made. We found a heterogeneous population with respect to the behavior of the vesicles. We categorized these observations with respect to the appearance of the lipid membrane to characterize the phenomenon.