I agree.
But here you address the issue of MA benefiting deliberatly a single player during gameplay. aka the MA employee who pushes a button.
But what about for example automatically adding a "luck" tag during avatar creation?
Or maybe players are randomly divided in large groups which get randomly different "luck" settings during a certain (long) period.
That way you could be so unfortunate to belong to a group which is due for "luck" for quite a while.
These systems can be fully automated and part of the game engine.
I know its all guessing, but Ive seen and still see results at players (and myself) that can't be explained by mere chance calculations and are surprisingly odd.
In cases like this I like to use Ockhams razor so when you exclude everything that isnt really possible the remaining theorie must be true