Well, nikcub isn't actually wrong. The CBA is the contract that dictates the relations between the league and the players association. It sets terms for the league, the salary cap, and the even procedures regarding the draft.

As far the cap goes, there are two caps: the soft cap and the hard cap. The soft cap is what you're probably referring to. The soft cap is usually broken all the time, as teams use it to retain players and whatnot. Think of 'Bird rights'.

The hard cap is what I imagine nikcub was referring to. A hard cap cannot be exceeded for any reason. Even in a sign-and-trade, since I think 2013, you'd have to waive a player to be below the cap, or make sure payroll is below the hard cap in the end.

In the context of nikcub's comment, I think he was referring to the hard cap.