Informal talks are very important in a bargaining session. A common principle of bargaining is that when you put something on the table, it's kind of hard to take it off again. That's why parties are careful to take small steps towards a goal.
An illustration was the Players' Association strong attempt to break the impasse last time around and avert a salary cap by offering the owners the alternative of a 24% wage rollback. In the end, they ended up with the cap, and the precise 24% cut they'd proposed as an alternative. Ouch.
So often, both sides know where a deal lies, what the figures and tradeoffs are going to be, but neither side wants to blurt it out at the table and weaken their position. If the two parties, usually the lead negotiators, can hold a sidebar or hallway meeting and test each other out, they can go back to their rooms and take the temperature, see if the direction they're headed in will work. While these sidebars kind of tip your hand a little bit, they're not as likely to be set in stone as if they're floated at the table with everyone taking notes.
All negotiations I've been in, the deadlocks broke during sidebar meetings late in the game, our rep would come back and say: "This is what we can get now, and I'm pretty sure we can win on these things if we give up on those, and this is the figure(s) we can probably get without going on strike. If we strike, we might push it to such and such, but..."
So be encouraged that the sides are meeting. Gary Bettman has a lot of room to move and still obtain a great deal for the owners. Don Fehr came in with a reasonable first offer and thus won the PR war, every reasonable observer has concluded that the players actually want a deal that will work for both sides, as opposed to the owners who are salivating at the thought of another great heist. But now Mr. Fehr doesn't really have any room to move, he can only take tiny steps.
Mr. Bettman has to swallow his pride and meet the players more than halfway if he wants a deal to prevent a lockout, and is more likely to do that in an informal meeting than at the table with a media session immediately afterwards. In an informal meeting, Mr. Bettman can move more freely and at the end when the deal is signed confess that the players showed imagination and flexibility in their willingness to work with him, that they won him over to their vision, and that they will enter a new, stronger partnership.
Again, there is a low probability that this will happen, but it is a greater one if informal talks are held rather than formal talks with a big group, or certainly greater than if no talks at all are held.