^ I don't think it's only a "Blindly Change Lanes" situation. At times, you have this little object going so quickly that you don't even see it approach.
On average, you're suppose to look at your mirrors every 12 seconds or so. Well, at that speed, something so small can be missed between those 12 seconds so if you swerve the opposite direction of where the driver is looking, the rider is VERY easily missed and bam! Accident. So, the cagger can be on the look out for riders as much as he wants, but if the rider is so quick...so much easier to miss.