Teaching with Moodle

Short answer is no.

Moodle requires that you are logged in as someone when browsing the course pages. So you'll need to require that students to at least use the "login as guest" button.

However, you can customise the login screen a lot by choosing a different authentication method (eg imap or db). You can change/remove the right-side instructions, and you can remove the change-password button.

On the flipside, using Moodle this way (as a simple content management system) means not using almost all of it's unique functionality. I don't know what your situation is but perhaps it's a thought to consider using student accounts and the advantages they offer for better online learning.