Prop 69 is aa real "long shot" on crime solving.
Previous criminals: you've got their DNA
Non-previous criminals (Suspects): get a warrant for DNA.
Not without Proposition 89 they didn't. One of its functions was to authorize the swabbing of prisoners and including their DNA signatures in a database.
Non-previous criminals (Suspects): get a warrant for DNA.
Proposition 69 doesn't affect suspects, permission or a warrant would still be required. All you're left arguing about is arrestees.