Taxiing in the grass was utterly nerve-racking. My Mooney's prop is inches from the ground, one sinkhole and I've tens of thousands in repairs. I did it, lots of Mooneys did. But I bet a few needed those repairs after some of the sinkholes I saw. And I was taught that flying in formation was done radio silent. I think the only exception was if you have an issue in flight, our aircraft are less than conductive to hand signals.