Deck construction is quite robust and regulated due to past accidents. Inexperienced builders, people not abiding by code requirements and known environmental conditions, i.e. salt, have warranted these mandates. The structural skeleton for decks do not rely on simple nails for the deck structure to remain integral. While the decking planks themselves may be nailed in place, they serve as a platform, not the structure. Heavy galvanized bolts connect the headers, columns, joists and stringers to form the structure and keep it intact from wind, flexing from other live loading conditions, etc.
An engineering evaluation will easily uncover the real problem. You can rely on the fact that the owners insurance company will have one performed!
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