This seems silly to me... Outside of combat, skill checks are considered to automatically roll 20. Is this just to simplify things for the single player game? Do we have the option to turn it off in mp? What is the point of having a skill check if you automatically get the highest possible?
Silly.

Actually, taking 20 is in the 3rd edition D&D rules. If you have nothing else going on around you (the game limits that to no combat, but in the pnp game, it can be no major distractions), and time is not an issue (once again, game is fudging a bit), you can take all the time you need on the skill, thus doing it carefully (thus scoring a 20 on your roll).

In the PnP game, you can take 10, too (in fact, the situation that you take 20 in NwN are pretty much the circumstances that you take 10 in the pnp game)