Originally Posted by
TheSummoner
Indeed. The important thing is that the enemy has to be willing to bend the knee in the first place.
That said, the Greyjoys did stay rather tame until Robert died and The War of Five Kings broke out. Tywin had no involvement in any of their uprisings, so it's difficult to say how he would've handled them. Had they rebelled against him, he might've given them one chance like Robert did, but he certainly wouldn't give them another if they decided to test him again.