I would say whether its from a LFS or from a local hobbyist, LR always has the potential to introduce parasites, pathogens and/or unwanted hitchhikers. Unless its dry rock, LR is a virtual breeding ground for both good and bad microfauna. IME, there really is no way to effectively guarantee a rock is clean unless you kill it all off which ultimately defeats the purpose. Therefore, if you know what kind of rock you are looking for (Tonga, Fiji, Caribbean, etc.) I would hunt down the best deal. Also, if you are buying online, don't bother paying extra for "cured" as it will still require cycling as there will be die off in transit.