Decks, Patios, Porches and Docks - support for a deck

I just had someone build a 16x24 foot deck extension. He did a great job overall, but I have one question. He used four 4x6 posts to hold the 24 foot width. He used 2x10's 16 inches off center.

However, he didn't notch (right word?) the 4x6's where the 2x10 header ran. He used four nails in each 4x6 post. He said this would be stronger than notching out the 4x6's.

I'm just inherently suspicious about nails hold weight. I'd like for him to go back now and use some large bolts to fasten the 2x10's to the 4x6 posts.

However, I am no carpenter. He insists that the deck is extremely strong and that no bolts are needed.

Is he right? Is there a building code section or some other authority I could refer to? Many thanks.

He should have notched the posts for the 2X10 beam to sit in as a bare minimum. (He should have used a dbl 2X10 for the beam and had it sitting on the top of the 4X6 post!) The nails won't hold squat -- have him put at least three 3/8" or larger through bolts through each of the posts and 2X10's.