Obviously not every Audi or BMW driver is an idiot but, sadly, from personal observation a lot of them appear be, judging by their way of driving. I drove my husband's BMW safely as did he and, strangely, we both got a lot less BMW drivers travelling half an inch off our back bumpers when we appeared to be 'one of them' than we did in any of our other cars (Fiat Panda, Zed, Evoque).
I don't think that the cars themselves make people into unsafe idiots but I do think that a lot of bad drivers are drawn to both BMWs and, latterly, Audis, for some reason - presumably the image that the manufacturers try to cultivate?