When you create an account you need to specify an email link to it. Once you are connected in this account you can, very easily, change the email link to your account :
Settings > Email > Save change
There is not check at all.
It could be interesting to have a security for this change.
- Ask for your password
- By sending an email to the first address you use and ask to click on a link
- Ask for a security question defined with the account creation
I am usingKOBO Humanitarian response
It could be a good improvement for security as for data protection ! It will avoid someone with bad intentions to change settings.