Second reason being, that not everybody is skilled and/or calm enough to deal with somebody bumping him from behind, and thus will likely screw up. It's okay, of course to put pressure on someone, but not if it involves contact.
Plus: We still have this issue that two cars sort of get stuck to each other, which makes bump drafting unpredictable.
Plus: We still have this issue that two cars sort of get stuck to each other, which makes bump drafting unpredictable.