My having no problem whatsoever telling the guy who hooked onto the back of me during my bike ride without even acknowledging his presence to get off of me. It scared the crap out of mr because I had no idea he was there. I happened to look down and saw his shadow, he was right on me. So I pulled to the right and yelled get off of me and sped up. I think he got the idea because I didn't see him again.