I realize that I'm probably late for the party here, but I just wanted to back the nay-sayers. Not because I'm some lame casual-player with no oldschool-streetcred wanting the game to be dumbed down or anything like that. I think auto-experience is important for the fluidity of a game. While I appreciate realism in games, there are certain aspects of life that I really don't want to have simulated in-game, because they don't add anything to the gaming experience. Eating and drinking for instance is awesome in real life because you can sense it. In-game it's just pesky. It may work if it's a key-feature but if it's just there for the sake of consequence and realism, it will be awful. That's also why you can swim in plate-armour and also why no character in any RPG ever actually wears a giant backpack.
If it's really only the logic that bugs you, Obsidian could simply add some lore that justifies shared XP or it's simply said that characters left in the tavern go adventuring on their own and are not able for a certain amount of time but may return with some minor valuables or something like that.