I was riding yesterday late afternoon to a restaurant. I was checking my mirros regularily (as you do) when I noticed that there was another motorcycle rider creeping closer behind me. I was not concerned at all and I figured he'd probably just ride behind in formation (I was riding on the right of the inner most lane). There were a set of lights up ahead which turned to green which meant that I only had to slow down for them while traffic picked up speed again. Once I passed the lights I was just about to check my mirror again when to my suprise the guy had just lane split to my left (used the left part of my lane). This caught me a little of guard and at the time as I thought it was a reasonably dangerous thing to do. Nothing happened out of it but we were coming up to a bend in the road in which case I could have easily collided with him if I decided change my position in the lane. He didn't give me any warning he was about to do this. What are everyone else's thoughts on this. I'm still a learner so I had no idea this might happen. I thought he'd just ride in formation. In hind sight maybe he did that delibaretly becuase of my L plate?