Sure. It should work the same as tablets that were never activated with a carrier. The "device activation has stopped" is just probably telling you you can't use the data connection the tablet was once on. Turn off mobile data and see if the notification goes away. What happens when you try to use it with wifi? Can you connect?
EDIT... You could also turn on Airplane mode (which will turn off all radios) and then turn on wifi. This way, there is also no cell communication with your old carrier in case they're sending the notification over the cell tower.