If a list is not moderated, your message will most likely be redistributed automatically by a program on the listserv computer without the owner first examining it. Your name is required only when you subscribe. Also, remember NOT to send your unsub request to the list itself. It won't get processed if you send it to the list itself and will probably get you a number of angry messages. There are a couple of things to remember about lists.
Some lists can generate many, many messages.
Also, if you join a lot of lists, you could wind up with hundreds of messages in your mailbox every day. When you leave, say for vacation or to go on a business trip, and you know you will not be checking your mail for a while, you may wind up with lots of messages in your mailbox. In either case, you might run out of disk space. It is your responsibility to maintain your lists properly and your disk space. Don't join more lists than you can handle.