rules question

[Spartan1983]

I played live for the 1st time a couple weeks back at Soaring Eagle in Mt. Pleasant MI. A player busted out and left, he returned a few orbits later and sat down to my right. He was probably about 6 seats from being the BB. I watched him take his chips out of the tray and stack them at the rail. I casually asked him if he was going to wait for the BB to post. He said yes. I turned my attention back to the dealer and waited for him to deal. I get my cards (don't remember what they were, but do remember I was going to play the hand). While I'm waiting for the action to come around I notice the "returning player" grabbing chips to bet, that's when I noticed he had been dealt in. When the action got to him,, I told the dealer he should have posted (Was I right pointing this out?) The dealer hesitates and says "oops, your right, my mistake" and then lets him bet.
What should have been the correct action to take by the dealer? Thanks, just curious. Neither one of us won the hand, not that it matters.