functionp

[Masinter.pa@Xerox.COM]

I've been staring at the spec, and I can't see what would prevent a
legitimate implementation from defining functionp from universally
returning T. "functionp is true if its argument is suitable for applying
to arguments". Now,

(lambda (1 2 &nosuchkey) ...) isn't suitable for applying to arguments
in the sense that funcall is guaranteed not to complain about it.  

I'm wondering if anyone has any portable code where "functionp" has any
meaningful uses?