I noticed that the latest update added check_plain to the Bean subject titles.
The Bean subject is the default implementation of a block title, and some people may want there to be some HTML in this title (such as a link).
Having the check_plain on the subject limits what a Drupal admin/developer can do with it.
Because the subject is hard-coded, there isn't any reason to check_plain it. Even if it weren't hard-coded, there's no way a non-privileged user can edit the title, so it's still secure to allow HTML.
Here's an example of why one might want HTML in the subject:
Our company has a couple custom Beans that provide default implementations of the block title (which is the Bean subject). We chose to make the Bean subject dynamically link to a taxonomy term associated with a given page that a user is on.