Well under your (joking) scheme Shed, Mr O'T has lost another 1% of his bonus - the notam is up until midday.
More seriously though, I just wonder if this is indicative of a major (handling?) problem which the airport are aware of and trying to resolve with the relevant parties, and this extreme measure is being taken in the meantime until an answer is found.
MAN has shown itself willing and capable of handling diversions, albeit it on a lesser scale than decades ago, and additional flights in recent years - remember the second snowy winter in 2010 (after a debacle the previous winter) when we took diversions from LHR when it snow-closed and then flights re-scheduled (e.g. CX) to MAN in the days that followed when LHR remained shut. Didn't we even get some praise from airlines for that response?
If however it is now an ongoing problem of staff shortages that isn't being addressed, or a measure taken because of the risk of bad
PR or because it's foggy and it makes operations more challenging, then it's not acceptable for an airport that brands itself as the Global Gateway of the North.