In a blog post, the Linux Mint team explained why unverified Flatpaks represented a very important security issue:
https://blog.linuxmint.com/?p=4675
The post highlighted the fact that users REALLY need to trust where they get their software from, and that for most unverified Flatpaks, building up that trust is not possible.
Verified Flatpaks now show their maintainer name.
Unverified Flatpaks are disabled by default.
A warning reminds you of the security risks associated with them.
Unverified Flatpaks are disabled by default
When enabled, these Flatpaks are clearly marked as unverified.
Unverified Flatpaks are clearly marked as such
Note that unverified Flatpaks also do not feature any reviews and do not have a score.