School choice policies can, by design or in implementation, give schools and districts discretion over enrollment. In this study, I examine the effect of local discretion over inter-district open enrollment on non-resident enrollment. I use longitudinal data on open enrollment patterns and policies in the metropolitan Detroit area. I find that when districts set more restrictive open enrollment policies, they enroll fewer new non-resident students overall, due to a decrease in new Black, Hispanic, and low-income non-resident students specifically. When districts allow inter-district open enrollment, racial and socioeconomic segregation within those districts do not change, and racial isolation slightly increases. My findings suggest that regulating enrollment policies to reduce discretionary exclusion can increase access to inter-district choice for some low-income and racially minoritized students, but that these kinds of policy changes are unlikely to reduce racial segregation and socioeconomic stratification more broadly.