MIGRATING PASSWORD SOLUTION:
Drew N (Community Manager) just asked this question in Homestead (Sitebuilder Plus):
Why is my page password protected when I didn't add it?
If you have a page that has become password protected and you never added the password, then it is because the password has been save in your browser and the browser is adding it to the field. When you save the page and publish, the browser has added the password to the page and it goes online. You will need to enter the password manager of the browser and locate the line for "sitebuilder.homestead.com" and remove it from the list.
Chrome:
1) Go to Settings and scroll down to the bottom and click Advanced.
Image https//d2r1vs3d9006apcloudfrontnet/s3_images/1630121/12868-vmlgk4_inlinepng1501706787
2) Scroll down to the Password section and click on Manage passwords
Image: https//d2r1vs3d9006apcloudfrontnet/s3_images/1630122/952-jnly4o_inlinepng1501707158
3) Find the Website sitebuilder.homestead.com and remove it.
Image https//d2r1vs3d9006apcloudfrontnet/s3_images/1630123/5151-4i3s1s_inlinepng1501707196
Firefox:
1) Open Options and click Security, then Saved Log ins. Then search for sitebuilder.homestead.com and remove it.
Image:
https://d2r1vs3d9006ap.cloudfront.net/s3_images/1630124/5151-1mvtcve_inline.png?1501707386This should prevent this from happening again.