I just climbed a big old English oak after a storm, I had to do some pruning where branches had broken out, and some end weight reduction.
While I was working on one large branch that had had two fair sized limbs twist and break out...I saw what looked like the end of a broken cable, then I realized it was solid, then I saw the bolts.
This branch, probably a good 12-16" diameter had three old through bolts in it, and sitting back and looking at it I could see where the split had been. Hard to say how long ago it had been bolted, but very interesting in that the failure of the limb was way out in front of the bolted section, the old split showed no signs of any movement at all.
It had only been bolted, there were no cables in it.
One of the branches that had broken came out of the bolted section, below and between the bolts. It had broken a good 5' out from the branch union. I actually left a fair sized stub, only cut back to just past the splintered section, my reasoning being that to introduce a fairly large (8-10") wound below and between the split and bolted section might not be a good idea...the branch was 'used' to that lower bit being there to help support the old split.
So there.