Yes, you could change MAX_MONEY later, but that would be a lot more obvious if someone attempted to change that in an update.

The question here is why were the daemons deliberately made to handle 100 million more coins than the given maximum? You also have to consider the amount that can be minted during the PoS phase. It is hard to predict the exact amount that can be minted in that phase due to the random rewards. But the code allows for a lot more than a maximum of 50 million.

The devs could come back and say "whoops, that was a typo, didn't mean to put 150 million there; update, no harm done." And they could fix the coin. But you have to ask why that number was there. It's a pretty big stretch to say it was an accident. There is zero legitimate reason for it.

The questionable motives behind that also make the anon system extremely risky. The anon system allows for the operators of the mixing pool to steal coins at will, and it would be very difficult to trace. Do you trust the people who slipped this variable change in to handle your coins honestly? Because that's what you would have to do. You're handing them a hundred dollar bill and saying, "Please give this to X."