Why would you actually want to include timestamps? IMHO, an error
return is better. There's no point in wanting to kick users who search
too often when you can just return an error instead.

I agree with you.

Also, I might agree that some commands might not need ACKing at all. I
can't think of such a command, though. I really do think that there
should be some kind of ACK for the search command, though. It would
be really useful to know when the search has been accepted.

command like public/private chat command may not need to have an ACK.
"Vote for Fredrik protocol" :-)

Eric