Different sensors may have different responses. A separate collection would likely avoid any particular biases that Google picked up, as well.
Then again, as someone who won't buy a self-driving car for as long as possible, it might be fun to learn the driving styles of different self-driving cars and use them to my advantage. E.g. If I know that tailgating a Prius which is going the speed limit in the left lane will cause it to move over in self-driving mode, or that a Mirai will always brake-check itself when it gets cut off, it might be possible to exert some control over them if it's advantageous in traffic to do so.
All the things you describe are as likely to cause accidents as wrong turns or over-acceleration. If Toyota can't get this right (my bet is they will) then they won't and shouldn't be doing autonomous cars, despite their "change of heart".
Pushing other peoples' cars around does sound kind of fun, but I hope we'll have something better to do than frustrate commuters.