When connecting to a paid network with Stampede sometime clients will see the following error:

A device 'slot' is allocated based on the amount of devices included in your payment plan. A 'slot' will be occupied by a device from the time it is first connected until it times out. The timeout length is set individually based on location. It is usually something between 2 and 12 hours. Once your devices has timed out a slot will be free and another one can be added.