Your point is well taken, but I still think that it would be better to simply enact a blanket restriction if that's the intent of the rule. There are almost certainly people who can and will take advantage of the rule as written (and perhaps people who already have), though I'm sure that it does indeed go some way toward making most players less inclined to do it.
If the thought behind the rule is that strategic secessions are somehow exploitative, unfair, or otherwise have a negative impact on the game then they should simply be banned in all cases; I fail to see why the rule is written with such narrow parameters if that's truly the reason for its existence, hence my earlier conclusion that that probably isn't the case.
Can you imagine the state of the game if we enacted blanket rules to prevent every avenue of exploitation?
