Since Target directly impacts production websites, it is crucial that:
1) There is advanced warning when Target will be inaccessible
2) There is the ability to deactivate Tests at any time – even during maintenance
Out of these 2 requests, #2 is the most important.
It is the most important because production issues don't care what time of day it is (though it does seem that most happen in the middle of the night! ). And when issues arise, the ability to stop a Test that is running in the impacted area needs to be available.