Many traits and (some feats, if my memory is right) have this rule written in them. For example:
Benefit(s): You gain a +1 trait bonus on Disable Device checks, and that skill is always a class skill for you. In addition, you can use Disable Device to disarm magic traps, like a rogue.
I'm unsure about the "always" word. Back in the days of 3.5, if you were spending points on cross-class skills, you got ½ of a rank per skill point spent. Thus, abilities that made a skill an always class skill was very usable for characters wanting to multiclass or take PrC.
In Pathfinder, only effect of skill being a class skill is +3 bonus. Thus, there is no sense to say that skill is always a class skill, right? It either is or is not?
Is there any meaning, rules-wise, to this always word in such rules? Am I forgetting something that makes it meaningful? Or is it but a reminiscent of D&D 3.5 era?