The reason the biker was on your arse is because some think they are invincible and have cow shit for brains some of them, loads round here anyway.
If a biker did this to me, sat up me behind, and I had to brake hard I would fuck em, they want to get killed let them, I have often pondered this very thing as what to do knowing the biker is going to get hurt, if something happens on the road and I need to brake heavy, but you cannot be responsible for thier actions and the danger they expose themslves to.
I would still sleep at night as well.
I move over for any biker that is at a reasonable distance behind obviously wanting to overtake, and I help by indicating a fewe flashes just so they know they normally say thanks.
Unfortunately there are a lot of idiot bikers, as there are car drivers, I think generally they are going so much faster that they stand out more as a problem
tabetha