Mac App Store Licensing (Not) Explained

This post refers to

Macworld’s attempts to explain the new license agreements for the Mac App Store still leave me puzzled:

The situation is slightly different for apps that are considered commercial or professional in nature. For apps that fall into this category—Aperture’s a good example—the Mac App Store license says that you essentially can install that item on computers you use or on a single computer shared by multiple people. Basically think of it as a one-seat license for a pro app.

What is considered a “pro” app? Is this something defined by the developer or Apple?

Things get even more confusing from there:

Now, let’s compare this news with the licensing rules I mentioned above. You can put two and two together, can’t you? Beyond entering in your Apple ID and password, this is all on the honor system. Just as you can install a single-user copy of iWork ’09 or iLife ’11 or Snow Leopard on an infinite number of Macs, you can install Mac App Store software on as many Macs as you can get your hands on. It’d just be against the terms of the Mac App Store you agreed to before you started buying things. Bad karma and all that.

For the most part this is how paid apps work now. Very few companies actually implement a software-enforced limit on the number of installs. So if you plan to install it on multiple machines you are on the honor system to pay for the volume pricing.

But with the App Store, I am not even sure how this would work. If I have multiple machines that use the same Apple account, is there even a way for me to pay for it again? Won’t it always tell me that I already paid for it and just let me download it?