in a arena, where u see ur oppoment, already sized him up. a smuggler woud be beaten down, maybe even without drawing his lightsabre ( lore wise ), possibly the same with a trooper....
but say on a jungle, like Kashyyyk or debris filled like taris..
a smuggler may be able to trap a jedi, or maybe even kill him out of a ambush. same with trooper.
and im sure a group of havoc squad could kill a jedi, NO PROBLEM