Sure, many people are aware of the NFL theorem, but they don't take it seriously.

Legg's thesis says:

Some, such as Edmonds (2006), argue that universal definitions of intelligence are impossible due to Wolpert’s so called “No Free Lunch” theorem (Wolpert and Macready, 1997). However this theorem, or any of the standard variants on it, cannot be applied to universal intelligence for the simple reason that we have not taken a uniform distribution over the space of environments. Instead we have used a highly non-uniform distribution based on Occam’s razor.

The No Free Lunch theorems seem obviously-irrelevant to me. I have never understood why they get cited so much.