The thing that concerns me with this scenario is the consent factor. It's just too dangerous, emotionally, physically and legally for my taste. Others will have a different threshold of course.
But one thing slightly annoys me. The assumption that a single guy should be willing to jump into the sack with anyone, like we should be grateful that we're getting laid. Some of us SMs prefer to have enough of a connection that we're willing to spend a few hours with a lady/couple before we part, most likely never to see each other again. This described scenario doesn't really allow for that. Speaking for myself, yeah I'm a man-whore, but I'm more than a dildo with a heartbeat. Some guys will be fine with that, others won't. Vive la difference.
I doubt that this is what the OP intended, but if I'm thinking it, I guarantee that some others are thinking this way as well, even if they're not saying it to avoid unpleasantness.