Yeah I was thinking it could have been something like that.
The only real issue I had with that was I was the last to respond. I had said the last thing, which was a question in both cases, and the model didn't respond to me. I'm pretty sure both times the question was, "are you ready" too.
I don't know how models see PM's. Is it the same as for premiums, where the thingy flashes if there's been an unread response?
Certainly I can understand getting a bazillion PM's as a model. But I think my issue was the fact that they had already replied, several times, and thus I thought we were in the middle of a conversation. If they hadn't replied to my first message then I would have understood that. As it happens that's what happened to a third model. I contacted her, got no reply so I moved on. Turns out her PM notification was broken and she didn't see them. Once she did notice she apologized, I said it was understandable and that was that.