That's patently ridiculous.
A warrior with no swords training can lead troops as effectively as a highly trained, multi-tournament victor. And if you go to a tournament, the worst thing that can happen when you lose is gaining only one honor, instead of three fame.
Courtiers with no skill can still work in the regions, and gain free training every turn, while still achieving something useful for themselves and the realm. The only thing that happens if they get a bad result on Survey Admin is that they get a "...Morale stays the same" instead of a "You've been captured, and risks facing execution."
A newbie priest can preach for hours on end. If he fails to sufficiently inspire the populace all that happens is that he doesn't gain followers. He does risk getting sliced and diced by the tax office guards while trying to escape a botched gold theft.
The point is that unlike any other class, an infiltrator with low skill is destined for swift capture and banishment, making him essentially useless, and opening him up to risk of execution even from a capture in a normal battle. No other class faces such a risk. It is this that makes infiltrators completely useless without the investment of significantly large amounts of gold over several months of continuous academy training. Infiltrators are also the only class that cannot effectively train in the field. Priests, courtiers, diplomats, etc. can all train risk free, and gold free, forever. Try taking a character and training his infil to 25% in the academy, then hit the field and see how long you stay alive.
I did this, and am still alive. Mind you that is mostly cause I got deported the few times execution was a real risk. I found that damaging production was a reasonable action that carried very little chance of me getting caught. Now that my infil is up around 70% from running these little missions, I can usually manage to stab a target without incident.
