I know about a year or so ago an absent players account didn't play DD's, Splits, Surendars on it's own. If they are allowing that now something is very wrong with that system.
Are you sure the player was not there? I'd bet they were and just not chating. It they do allow the system to play for an absent player that could be a big advantage for BOT's to play for the house and rip of the players. Not saying that happend, but I sure wouldn't play there if what you are saying is correct.
You aren't confusing blackjack.com with blackjack21.com, are you? The system there deals with absentees like this -
- The colour of the button by each player's name indicates whether or not that player is connected.
- The system will stand on any bustable hand, otherwise hit. (At least, I think that's the only rule being followed.)
- After two thirds of the rounds, absentees are ejected from the game.
The only problem I have with this arrangement, is that the ejections are done manually by the 'tournament director', not automatically by the system. This means you can't be certain precisely which round it will happen in, and so you can't predict who will be acting first on the final round.
I don't know how that system deals with players who are connected, but not interacting with the system (e.g., fallen asleep

), or with intermittent loss of connection. I have a terrible feeling that if you happen to lose your connection at the point where the tournament director is checking the tables for absentees, you might get thrown out, even though you've been playing up to that point!
I'm not sure your concern about bots is altogether justified. The only difference I can see, with the system playing out hands, is that you can't treat an absence of chat as an indication that a player might be a bot (since they might be an absentee). At UBT, I used to regularly play with chat disabled. At Global Player, I didn't always open up the chat application. How was anyone to know whether I was real, or a bot?
Actually, a thought has just struck me - At blackjack.com do absent players still bet the minimum on every hand? That would be a pretty useless strategy for a bot!
If absent players don't just bet the minimum, but actively follow tournament betting strategies, that would be far more significant than how they play the hands they are dealt.
I think the following are, in order of importance, the key rules which any online BJT ought to follow for the handling of absent players -
- Eject them from the game automatically at a predictable point. (such as UBT's after five consecutive rounds of no interaction.)
- Place minimum bets for them.
- Play their hands using a simple stratgey that takes no account of other players' hands. (This could be 'stand on everything', Basic Strategy, or something in between.)