Comment 6 for bug 902807

I can see why "Stop" and "Pause" might be considered a good idea, but I agree with Astuur's comment #4 - it's a very elegant solution in several ways:
No additional UI elements are needed. The cleaner the UI the better.
No explanation needed for the difference between "Stop" and "Pause".
The automatic priority adjustment uses existing game logic to achieve the desired result.

Automatically reducing the priority means the site will not receive wares that are needed elsewhere. Once the required wares are excess they will then be supplied, which is optimal. When a site needs a ware I want it delivered. When I have excess wares I want them delivered where they "can" be useful later.

In my opinion emptying a bakery of flour and water when it is stopped is not efficient. If my economy is so low on flour/water that I need every single ware I will use the ware storage buttons to remove them. I would say this scenario is rare enough to leave it to the user to remove the wares if this happens.