MVFR = VFR. There is no delineation.
This guy was wrong to do this and especially take people with him. Also sounds like he busted the minimums over built up areas. If this had been NM desert, then it would have been a complete other kettle of fish.
However, here in SoCal, there's a lack of bad weather training and experience. Many people go from zero to a PPL without even having seen many clouds. When I go fly with ceilings around 2000ft here in the basin, the airspace is empty of VFR traffic. Literally. Nobody flies in SoCal in marginal weather.If we did that where I first learned to fly (wx like Alaska), we wouldn't be flying at all for 10 months out of the year. It's an essential skill to have marginal wx experience and it should be practiced. They way you practice it is to go out and fly it. But preferably on your own. You'd be surprised just how bad 1 mile visibility actually is - not very fun to fly in. Thankfully, it's rarely ever that bad here.