A couple of years back I parked at all of those in the course of section hiking the trail over the span of three years. We had heard some talk about break-ins at a lot north of Smuggler's Notch, but in all the folks we encountered, we never heard of any mention, and I never saw any broken glass or cause for worry.
I think what happens with a lot of trails is that there's a break-in once, or some drug addict goes on a spree for a while before getting caught, and then the reputation of that lot goes on for years and years.
For whatever that was worth, which, upon reflection, wasn't much!
Brian