Why You Don't Caulk Exposed Nails?

Caulking exposed nails on flashings(Leave me alone Spellckeck dude. You don't even recognize yourself in the mirror.) and the last piece of ridge is a complete waste of time and can cause more harm than good. We don't want those flashings (ditto)to blow off so we nail them on the face and the last piece of ridge cannot be blind nailed simply because it is the last. Blind nailing means the nails are not exposed "to the weather." You can't see them
Home inspectors brought in on real estate transactions have been requiring this for several years now but for many a moon we left them exposed successfully. That caulk will not help and may cause more problems.
There are three ways to waterproof:
1) Turn the water using gravity pull the water downward, cascading from one shingle out onto the other.
2) Seal out the water with adhesives such as caulk or pookie (plastic cement, a word.) or, as in the case of flat roofs, making a giant bathtub-like liner out of the roof system deemed for the job.
3) Lastly is the compression seal. Mechanics use this to keep gaskets from leaking just as wine makers use cork to keep the wine in the bottle fresh.
Back up on the roof imagine a nail being hammered through a piece of metal flashing with a couple of layers of overlapping shingles underneath it. The sun never shines there and the nail is flush. The head of the nails is tight keeping almost all the water out but the shank is gasketed (it's a word in Texas Mr. Spellcheck)by the metal and at least two layers of roofing material. That cork will be like the Dead Sea Scrolls, never exposed to the destructive powers of the subatomic radiation of the sun.
Now imagine the caulk on it. Will it discolor? Is it silicone that will lay on the flashing but allow water to get under it in a short period of time, making the metal rust? Maybe it is a metal caulk that does its job and makes you have to demolish the flashing to move it or reset it. The roofer probably used whatever he had. It doesn't matter. All are failures.
Don't believe me? Do you think this will leak without it or won't cause a problem for the next guy? Ask Gerard, Stonehenge, Decra, Atas, Metro, and a host of others that are made in the USA, Canada, Jamaica, Korea, Mexico, China, New Zealand, Australia, and Mars (projected to open in 2025. Since 1957, all over the world, hundreds of thousands of roofs with thousands of panels with tens of thousands of exposed nails have been put up without caulking the nails. Why has it all of a sudden necessary to caulk the nails. If this were true a new industry would be born and the unemployment rate would fall to negative numbers. We'd need more immigrants and domestic births. It would take many lifespans to correct this egregious crime of moral turpitude. There ought to be a law. Oops, I think there is one somewhere. It has sprung from the primordial soup because it sounds good: CAULK IT!
Give me a break and think before you start making me put out an inferior product because it sounds good on the surface, just like caulk on a flashing nail.