I don't even have to tempt the rebels to attack me. I just walked into Helvetis with two fullstacks and was swarmed by 3 fullstacks of mori gaesum, mala gaeroas, epos and brihentin the moment I cleared the border. Before I knew what hit me I was reeling back across the border with 50% decimated armies. Victorious, of course, having destroyed all three, but wow.