You may have recently read stories about an "new" Android security issue which has been called "Certifi-Gate".http://www.techrepublic.com/article/scan-your-android-for-certifi-gate-vulnerability/
Essentially, remote support applications, like TeamViewer Quicksupport, Mobizen MobileSupport etc use a special plugin so they can read the screen. These plugins are signed by the manufacturers, like Samsung, LG, etc.
For a few months now Recordable has been using the TeamViewer Quicksupport plugin to allow users to read the screen without activating over USB.
Both Recordable and Quicksupport inform you when they are reading the screen, but it is possible a malicious app could use the plugin to start reading the screen without telling you. So, if you have installed the plugin and are concerned about malicious apps you might want to consider uninstalling the plugin when you're not using it.
USB activation is secure. Each USB activation generates a new, random key which only the Recordable application knows.