I think it's even simpler than spying on the QB... you just take the backside edge guy (OLB in this case) and tell him to go attack the QB until they're sure the QB doesn't have the ball.... that's what happen last week when the Packers went for play action and it failed because the back-up DE attacked the QB (and didn't bite on the run action) and was in Rodgers face when he turned around and just lunched it not to take the hit.... I'm trying to remember, he got intentional grounding on that play right?
Now if the back side edge guy is targeting the QB like I suggested above then someone behind him has to come up for containment on the backside or possible runs or the RB will just go to the backside (or they'll call a counter) but this is how I think most (like the Ravens) handle stopping the read option. Front side attacks the RB, backside attacks the QB... and new containment guy for the backside to stop the RB from sneaking out the back.
The problem has been the Packers have either had their OLB playing to keep the containment, or the backside has been attacking the RB when they think it's a run, and we love it when Matthews catches the RB from the backside for a lost, but that over aggressiveness on the RB burned him when going against read option (and did last week on one play).