And this is why I encourage the ability to keep things secret from players as well as characters. ;) But diving in:
Avraham, runekyndig isn't bringing this up because he's looking to do anything metagamey. He's seeing what he views as a potential problem (signs of another player putting something higher in value than party unity) and, since he doesn't know you, he's trying to provide kind of a soft warning of, "Hey, this might not be the best way to go about doing things as a group." It's a fair thing to point out, and I commend him for both having the conviction to bring it up and the manner in which he approached it.
Now, that said, runekyndig, Avraham's points regarding why he would somehow stand out at this juncture while nobody else in the tavern does are well made. As indicated, he has cleared with me his intentions and how they might manifest. I won't share the details of that because they're not mine to share, but I will note that I've asked for Deception checks from him regarding anything that might be untoward or dishonest in his approach. You are welcome - nay, encouraged - to make insight checks regarding any parts of his presentation that stick out to you. I will compare your insight roll to his deception roll, make my own private adjudication regarding whether your suspicions have merit, and I will inform you accordingly.
Avraham, I don't want to allude generally to what does and doesn't warrant suspicion, but I would point out that eventually, the Baron's going to come and you're going to wind up revealing your marker (or, I suppose, just not joining the group and making me run a solo game for you in town. :) Wouldn't be the first time.) At that juncture, I think a little retroactive wariness on Hal's part would be more than justified. You may have tipped your hand a bit early here. ;)
Edit: Aaaaand I just caught up on the IC thread, and I guess that revelation happened already, followed by a fairly blunt confrontation. Spicy. :)
Well, I stand by what I said, a little wariness at this point is fair. Though I would definitely cry foul if anyone immediately jumped to, "You lied about your name, then, didn't you!" That would be quite the leap.