  Generic models of propelled particle systems posit that the emergence of
polar order is driven by the competition between local alignment and noise.
Although this notion has been confirmed employing the Boltzmann equation, the
range of applicability of this equation remains elusive. We introduce a broad
class of mesoscopic collision rules and analyze the prerequisites for the
emergence of polar order in the framework of kinetic theory. Our findings
suggest that a Boltzmann approach is appropriate for weakly aligning systems
but is incompatible with experiments on cluster forming systems.
