Late arrivals position

Question. We play a friendly cash game. Late arrivals are required to post their blind upon arrival regardless of where they are seated. Last night two people arrived late at the same time. They sat down to the immediate left of the big blind and immediately posted as requied. Betting went around the table and big blind checked. Then player to left of big blind checked and player to his left bet. I said you cant bet after big blind checks. Everyone said i was wrong. My thinking was they should have been first to act. The only way to to steal position from big blind is to straddle with twice the blind. Everyone said i was wrong. How am I wrong? The way they did this made no sense at all to me.

You are correct. Action should have begun with the player to the left of the big blind. The first late arrival.

If two new players sit down to the immediate left of the BB, they are not required to post in my home game. If they are in a casino and are required to post, they can choose to sit out for a couple of hands until the BB reaches them. These players are "new" not "late". In a cardroom, I like to wait, watch and straddle in if this is possible.

In any event, in your described scenario, action should have started with the new player on the immediate left of the BB. Since he already posted, he could have decided to check or raise. the same applies to the next new player who posted. After that, in a limped pot, action should close with BB. If the pot is limped and BB checks his option, how is it possible that action is not closed? I don't really understand what has happened here. Did action start with UTG +2??? If so, that is the (bizarre) mistake here. Having to post is not a "granting of position" - it is simply an obligation to pay blinds that others have paid (and newcomer/returning player has not). Out of position blind posting does not change the order of action in any way. This is why in a cardroom, a new player just sits (wherever) and is offered the option of waiting for the BB to come to his position, or posting a big blind and playing from the next hand - or second hand if this would interfere with button.

Good explanation. Thank you. I don't think the new arrivals said check or bet to begin the action. It just kind of went around and kept going. Lots of conversation was happening as action started.