How does grey Market get fresh purchased Rolex’s, almost immediately after they’re bought?

I’m wondering how it’s possible for Grey Market dealers to get brand new watches. Given how long and how much work it takes to get a watch from an AD, it makes no sense that soooo many watches make it to the grey market IMMEDIATELY after they’re purchased. I’ve heard that if you resell, you’ll never be able to buy new again and there is no way people are risking that on a daily basis. Maybe I don’t fully understand the process, as I’ve only bought grey market and they’ve been a few years old… But I feel that I see brand new Rolex’s hit the grey market ALL THE TIME.