This does happen from time to time. We have shipments arriving a few times a week. But sometimes we do run out of items if all of a sudden they become more popular at the time.

We don't use an option of out of stock on the cart because people pay for items in all sorts of manners, and if we allocated those items to a customer who doesn't pay for 2 weeks, then someone else could've had it first. Also our package deals use the same inventory as individual items.

Now if you happen to order something that becomes out of stock in the mean time, you will be contacted with an expected eta of these items, or asked if you would like to change the item to avoid delays.