[chalst]

considerable resources

This is a British university, not Goldman Sachs. The action was a dramatic, low-cost effort to get users' attention, educating users, if you like (from OP):

> While this wouldn’t be effective for users on other networks, in the middle of the working day a substantial proportion of users would be on our network and actively reading email. A temporary block would get users’ attention and, we hoped, serve to moderate the “chain reaction”.

[blisterpeanuts]

"get users' attention"

I took that to mean, we were planning a longer term outage, but when it inconvenienced Someone Important, we were forced to reinstate the service, and to cover our rears, we're now claiming it was planned as a 2-hour outage from the very start.