How will you noticed if someone says he had a bike? Look down. Way down there, unto their shoe(left). Stay focused then compared it with the right shoe. Never mind the size of it ;). If you consider yourself as a commuter people, using your MC for daily purposes and not using rider-grade shoes, much likely your shoes are just like these.
This sign are noticeable if and only if they driving MC with shift gears. Otherwise they owned a scooter, if they insist they are rider.