I should have warned the OP that this is one of those topics where it is impossible to get honest responses without 100 unilateral responses of "not safe, never do it, its never okay, I am 100% sure you will die" etc etc...
All of us take part in at least one practice considered unsafe by others (like running no blinkers). Hell riding a motorcycle at all is considered by many to be a death sentence. The fact is it all comes down to the awareness of the rider and the manner in which the bike is ridden. I know it is sacrilege to admit, but I've retrofitted Bluetooth into my helmet and I often stream music at a reasonable volume while riding, and I adjust my riding style accordingly.