My thoughts are that if you're at the front, in gear and you see numpty coming up behind you, it would be instinctive to drop the clutch and get away.
Problems arise when the cross traffic arrives at the same point on the bitumen as you.
I prefer to keep an eye on numpty and if the need arises, step off the bike.
Had something similar about 3 years ago but I didn't see him coming ( I was at a STOP sign and looking to my right at the time), he hit me and pushed me out into cross traffic where I nearly became a speed-hump.
Dave