So lets focus in on this statement a bit and I offer a revised version of my question....
In a world where sorcerers can already cast spells not using components how would a second class being introduced also able to cast spells not using components alter how NPCs operate?
So, there are a few points here that need addressing.
1) Sorcerers are born, meanwhile most psions are generally seen as training, similiar to how monks operate. This makes Sorcerers not only rarer, but you cannot choose to become a sorcerer. You would be able to train and become a Psion, making them far more common.
2) Sorcerers need to reach level 3, and pick subtle spell, to be able to cast three spells without components. So, if we started with saying that a Sorcerer is a 1 in 100,000 birth (number chosen randomly), and each level drops the number of people in the pool by 10%, then a 3rd level sorcerer is about a 1 in 10,000,000 occurrence. Making them even more rare.
3) A 3rd level sorcerer is allowed to pick two metamagics, out of a collection of eight. Brute forcing some math, I think there are about 28 combinations of metamagic, only seven of them include subtle spell, which gives you about a 25% chance of having subtle spell on your list. I think that drops us to about 1 in 100,000,000 if I'm any good at this style of math.
This leaves us a very very small percentage of people who are even capable of this feat, let alone actually having the desire to cause any trouble.
I haven't mentioned Psions during points 2 and 3, because per how this is being presented, every psion starts with this ability at first level, meaning those extra steps of rarity do not come into play. And remember, Psions are generally someone who can be trained, meaning they are only as rare as the people who can train them. So, a secret cabal of psionic assassins is actually incredibly likely, especially compared to a cabal of Sorcererous Silent Spell Assassins which is nearly impossible to actually have.
And, this is the core problem to face. If Psions can be trained, and they can be so immensely powerful, everyone will want to train them. Or, barring that, kill them so that they cannot be used against them.