You may not abridge someone's civil rights without due process... The burden of proof is on the state. The accused is presumed innocent until proven guilty.Should we have some restrictions or is every breathing person fair game? This would get tricky.
90% of the population are not trained gun gurus like NESers...
If they are too dangerous to have a gun, they are too dangerous to release from jail - the sentence for any crime should make this clear...
There are no reasonable restrictions outside due process as far as I am concerned.