It's not too hard a situation to imagine...
You're logged in to a website, and you walk away from the PC. Someone comes along and starts using the same website. If they submit a form, then it shouldn't update your CRM record. It should show them that you're still logged in. They will then log out and create a new CRM record.
This problem was initially reported here -> https://roadmap.siteglide.com/bugs/p/forms-overwriting-crm-records After much discussion here's measures we've taken to make this easier to implement for you.
Our default form layout for new or updated forms will set both 'email' and 'name' as readonly, pre-populated fields if there's a logged in user.
You can also add your own message on page like this:
If you look at the email and name fields in your new default layout, you'll see this:
Either remove 'readonly' to allow editing, or remove the entire IF statement if you also don't want it pre-populated.