When you attempt a trip after an opponent is entangled in a snag net, does it provoke an attack of opportunity by the entangled opponent? I'm thinking yes, at a -2.
If you are in reach of the entangled foe and do not have improved trip, you provoke. However, you can make a trip attempt at 10' while holding the rope, so if your opponent doesn't have reach, you can make the trip without provoking.