Reminds me of a game-breaking strategy in the (interesting, flawed) hybrid RTS/RPG War in Middle Earth (1988).

The RTS part involved moving armies and heroes around to fight Sauron / Saruman’s armies and defend your citadels. There was a game loss condition if you lost something like three citadels in battle.

But if you abandoned your citadels, their subsequent occupation didn’t trigger the loss. So you could simply aggregate all your forces into one giant army and take Barad Dur and Mt Doom by force.

Probably an under-appreciated game, historically.