2 people arrested after Waymo alerted San Francisco police about loaded rifle

Someone very likely 3d printed an AR lower (unserialized, therefore a "ghost gun"), unlikely it had an autosear. The news and police typically call disfavored semi-auto weapons "assault rifles" and things that are fully automatic "machine guns".

All of these are true: the cops are untrustworthy; a bust like this gets overhyped and both the government issued information and the reporting are inaccurate; pedantry about select fire modes is pointless; Americans have a right to buy military style weapons, and that's in the context of the drafting of the 2A, unless you are not white enough; modern military style weapons are pointless in the hands of all about a very few civilian marksmen - they are fetish items.

All the press announcement needed to say to get the correct point across was that somebody was brandishing a weapon in a Waymo, they got caught doing it, and the police responded and arrested them.

This newer incident likely won't be as controversial since the riders had actual weapons, not toys; and no claim that the Waymo "imprisoned" the riders, as many people seem to have previously hallucinated.