Surely low-quality traffic is traffic which doesn't convert for you personally? ..one man's poor quality traffic may be another man's gold mine. Don't ever confuse low conversion with fraud traffic (it can be down to all sorts of things), but it's equally true to say you'll never convert a bot!
Well if you want traffic buying to be safe and transparent I'll happily let you run a traffic campaign through our systems - it will soon tell you if what you're buying is just badly convert or fraud traffic. Want to know more then this tells you more!