Does shield dust prevent all damaging and status effects from Max moves and G-max moves?
G max Snooze has only one effect, putting the target to sleep. Shield Dust only blocks out secondary effects, not primary like toxic, yawn, hypnosis, spore, you get the idea.
The only way to prove it is to test it.
I did and here's the replay: (Grimmsnarl VS Frostmoth) (no items) (prankster and shield dust)