Asking forgiveness entails taking a personal risk. If it works out, you're wonderful. If it doesn't work out, you have to answer for your bad judgment.

Asking permission is a way of hedging against your own judgment. In other words, it's a great thing to do when you're genuinely not sure. But if you are right, you don't get results as efficiently, since you have to let everyone bikeshed first. Maybe you don't even get results at all.