I wonder how they get confirmations before they move to the next stage.
Bear with my following stream of consciousness - there's a rational thought in there somewhere, I promise.
I've always though it strange that we say it takes 10, 30, 60 minutes for bitcoin to confirm like it's a bad thing, or like that is particularly slow. I think it's a failing of grammar on our part. Let's compare crypto with a credit card. I eat a meal and pay by credit card. It takes a minute or two with a card machine, and then my transaction is paid, right? Nope. My transaction has reached the credit card company's servers. It will take several days before the money actually reaches the restaurant's bank account. In that time, a lot of things could happen. I could call up and dispute the charge. I could claim my card was lost or stolen. I could claim I was defrauded. I could max my card out and not have the funds to pay it. Etc. Etc. There's loads of things that could happen in those three days that would leave somebody, either the restaurant or the credit card company, out of pocket for my meal.
Now, compare that to paying with bitcoin. I eat a meal and pay with bitcoin. It takes 20 seconds for me to open my wallet and scan the QR code. My transaction is immediately broadcast. In 20-30 minutes (usually, depending on the fees, block frequency, etc, but certainly nowhere near 3 days), my bitcoin reaches the restaurant's wallet. What can I do in those 30 minutes to stop that transaction happening? Launch a 51% attack on bitcoin for the sake of 50-100 bucks? Laughable really.
An unconfirmed bitcoin transaction is both a lot more secure and a lot more rapid to "confirm" than an "unconfirmed" credit card transaction. I think we as a community don't do a great job of explaining that to people. 20-30 minutes is lightning (pardon the pun) fast compared to credit cards, and a lot more difficult to reverse once broadcast.
So to answer your question, they probably don't wait for confirmations. Once a transaction has been broadcast, and you can see it's not been broadcast with 0 fee, you are quite safe to move on, provided it's for an everyday sum of money. If you are selling cars or real estate, then sure, wait for some confirmations first.