We picked up a straggler one time and he kept "sling shotting" behind us.
That means he would fall way behind, then speed to catch up. Then drag ass behind, speed to catch up. ect ect
To make a long gory story short, we (the orginal riding buddies) decided to pull off for some gas and this guy wasn't paying any attention and as we slowed down to turn into the gas station he was gainging speed trying to catch up, then he slammed on his breaks and I saw him and the bike tumbling down the highway in my rearview mirror.
To make a long story short he was Life Flighted outta there on a Helicopter than landed in the highway.
We didn't even know they guy. So you don't have a clue with stragglers if they know how to ride or not.