If an OL flinches without a false/deceiving move by the DL, it would still be a penalty on the OL. Bassically, if 3 DL stem to the right in unison before the snap, and the left guard jumps, it's a false start on the OL. But if 2 of those DL stem to the right, and the 3rd just moves his arm quickly like he's about to move or rush, but doesn't, causing the right tackle to jump, it's a 5 yard penalty to the DL. It isn't something that should come into play often, IMO.