"Operation not permitted" on directories... expected?

[Matthew Woehlke]

grep 2.5.4 on ppc/Darwin

If I do something like 'grep foo *', I get the error "grep: bar: 
Operation not permitted" (for all directories "bar" in "*"). That 
doesn't happen on Fedora with F10's grep (2.5.1 with unknown patches), 
and I don't remember seeing it previously elsewhere.

Is this an intended behavior, or a bug?

--
Matthew
Please do not quote my e-mail address unobfuscated in message bodies.
--
"I like to think of it as 'unplanned dissonance'" -- A fellow chorister