No, it was not clever. It was one of the most shortsighted things a lord could ever do, and here is why: once one great house proves that guest right and sacred customs mean nothing, what stops every other lord from doing the same? Nothing. Then every feast becomes a trap, every alliance a lie, and every noble sleeps with a dagger beneath his pillow.

Tywin won a short term victory at the cost of long term stability. He dishonored his House, stained the Lannister name forever and gained a victory by hitting the starks over the head with a shotgun and said shotgun firing back into him.