By adding the following code to your page layout, you can target any page where there's a password field and this code will automatically set a default random password for the person.
This will also set a cookie so they'll be logged in for a period of time. However, if they try to do from another browser, they'll be required to either reset the password or if you search or blogs, you'll find an article about setting up a magic link email.
<script type="text/javascript"> if (curPath == 'checkout.aspx') { var uq = Math.random().toString(36).slice(2) + 'X!3'; $("#content_password_confirm").val(uq); $("#content_password").val(uq); $("#content_password_confirm").closest("li.gridList-item").hide(); $("#content_password").closest("li.gridList-item").hide(); }</script>You can also target specific checkout scenarios by targeting the curObj.reference_type and/or curObj.reference_no.