I'm sure that Chanserv like any good bot won't respond to a privmsg with a privmsg, but with a notice.
From the RFC:
The NOTICE message is used similarly to PRIVMSG. The difference
between NOTICE and PRIVMSG is that automatic replies must never be
sent in response to a NOTICE message. This rule applies to servers
too - they must not send any error reply back to the client on
receipt of a notice. The object of this rule is to avoid loops
between a client automatically sending something in response to
something it received. This is typically used by automatons (clients
with either an AI or other interactive program controlling their
actions) which are always seen to be replying lest they end up in a
loop with another automaton.