I don't like the hold-down requirement, but I can understand the position of the code writing and code enforcement folks. As Mike points out, bad flashing is probably why most decks fail. Unfortunately, flashing isn't really inspectable, in the standard single-family-home style of inspection. Commercial-special-inspection style, yes, you could verify the flashing, and if that were really a solution, I'd be fine paying a couple hundred dollars to get a special inspection for the flashing. But the best flashing job in the world is easily negated by some idiot doing a bad window or door install above the deck.
Hold-downs, on the other hand, are easily inspected, and they're durable: they're far enough inside the building envelope that if the flashing fails (yes, I realize that good flashing is a necessity in any case) and the rim rots away, the deck probably won't fall to the ground.
I don't think that you can simply say that people should just hire good deck builders instead of hacks. Of course that's true, but is no more relevant to decks than to any other aspect of building.
Unfortunately, even the hold-downs aren't a perfect solution. Aside from the high cost for remodels especially, most builders are going to have as many or more problems flashing around hold-down penetrations.
The solution? Someone out there needs to come up with a complete deck attachment system that solves the structural and weatherproofing problem, for new and remodel work, that doesn't require breaking into the inside of the house. Maybe it's out there, but I haven't seen it. It has to offer a real solution to the weatherproofing part of the problem.
It's a bit of a random thought, but the codes don't really accommodate the fact that decks are not and haven't been treated as permanent structures, expected to last as long as the rest of the building. There are exceptions, but they're rare. I don't know where that leads, but it does make decks different from other parts of most houses.
It's obvious that current practices just aren't cutting it, in the real world. And because codes are not about best practices, but about general practices, we have this reaction in the code writing business.
Those are my thoughts, anyway.
- Bob