If a policeman asks you to get out of your car without justification you can bet they're the sort that are more likely to not be disciplined with their use of force either. Police are always quick to cite this case but generally they're ignorant of what it says, they just mindlessly say "pennsylvania v Mimms" everytime they want to be a dick to someone by inconveniencing them or to incite an arrest of someone they think won't want to leave their car. Look up "Civil Rights Lawyer" online and he even uses PA v Mimms against one officer ordering someone out in a case because their order was unlawful.