Where do I get a concealed weapon to carry with me into the casinos? In the previews, I saw a guy running up to you and offering to sell them but that never happened to me?

Those weapons are pistols and small meele weapons , so you cant sneak a rifle past them.

Pick up a silenced .22 handgun, and a razor. You can find those all over the place.

Thats the only two things I can bring in right now.

There's a guy standing outside Gammorah who sells these.

Small meele/unarmed weapons, pistols and grenades. A silenced pistol with HP rounds does the trick for me.

there should be a guy outside of the gomorrah casino (the one across from the lucky 38) named mister conceal hes in a pinstripe jacket and usually leaning on one of the walls. he offers to sell you concealed weapons

So a normal silenced .22 can also be sneaked inside? The weapons don't have to be labeled 'concealed'?

no , they are no labeled , its strange , i managed to sneak past energy pistols without a problem with a sneak 50 check.

So the higher sneak you have, the better weapons you can bring in?

Im at only 30 or so and could only get the two weapons I just mentioned in. I had plenty of grenades on me too.

Does anybody know if my companion picks up say a pool cue in the middle of a fight in the casino, and walks around with it on his back, will that have repercusions?

No Sneak doesn't matter. It's odd, but sneak is required to even get the holdout option for one hotel, I think de-luxe. Otherwise, sneak has nothing to do with anything.

You can sneak in small pistols and hand weapons. 9mm and silenced .22 confirmed by me. Though the silenced .22 is an awful gun. That Gun cannot be snuck in and I would be surprised if any revolvers could be.