In Swiss architecture, it is very common for sills to be joined together with a keyed double tenon. The tenons pass far out the other side, and are secured in place with a strong key, creating a joint which can move no where.
The preferred practice in this situation is that the key be square and straight, not tapered. This requires the joint to be very carefully formed as you cannot rely on a wedged key to draw it together. But the thought is that it is stronger this way. Also, a straight key does not work itself out over time.
And then, on framed buildings, pegging is often totally absent.
