The password security requirement is not only limited to customer credit card information, tmick31.

As what @qbteachmt mentioned above, having your company's FEIN will trigger the password security. Not only that, there are at least twelve Personally Identifiable Information (PII) that QuickBooks detects to require a password.

When you have one of these information, then there will be no option to remove the password. The Master Admin will be asked to change the password every 90 days. 

The purpose of this is to ensure that the person who will access the file is totally authorized. You can learn more about it here: Password security for QuickBooks Desktop.

Just read through the article and leave a reply if you have questions.