"Illiquid" is not hedgie code for retail won't be filled on the smallest of orders. It is a term widely and commonly used.
I have been filed in illiquid securities before all the time. The most recent one I was filled on was a Lehman security tied to GM senior bonds which I made out nicely.
Illiquid means there are just not a lot of buyers or sellers. That creates an illiquid market. Supply and demand. You can't expect a market maker to sit around all day to fill your ticket while the other securities and trading at high frequency. Lets be realist please...
Do you own LEH cap trusts? If you do, then you were filled, right?
BTW, I am not the kind of person who cheers along with the "perfect storm" crew, and then when they are gone and no more cheering, blame anyone, including them for reality. Just have to face reality and the choices YOU make/made.