Mailing list question

Silly questions really but ...

#1 all the messages I receive from the GENERAL mailing list have the To:
field set to be the original poster, CC: set to the ML address, and
there is no Reply-To: field set ... is this normal?

The reason I ask is that I find myself sometimes replying to a ML
message and sending my reply to the individual rather than the ML ... In
order to avoid this I have to hit reply-all and delete the OP's address
... a bit annoying.

Or is is standard ML practice/etiquette that I should send replies to
both the ML *and* OP?

Thanks!

Jc