However there is a problem with this. As it turns out, farmland is not a "solid" block. It has a small gap at the top. And with the changes made a while back about a block's hit-box being exactly what you see...
As it turns out squid CAN and WILL aim in the teeny-tiny gap under the half-slabs and snag you. They will throw you up in the air. You take falling damage, and worse trample your crops...
So...anyone else tried being a smart-ass and got bitten for it like me?