hardest to stop. Even if the offensive coach tells the defensive coach the call ahead of time its still going to work more often than any non qb run or pass.
I mean the stats show that its not close. QB sneak works 82% of the time. That is WAY more often than any other play. And remember that a qb sneak formation is up to the line of scrimmage with extra tight ends in an I-formation. When the qb sneak is ran it isn't exactly a secret what is coming. The defense clogs the middle and sells out to stop it. And still rarely stop it.