I use Avast 'Bank Mode' to watch Cable TV online. Sometimes I want to record video. So, in 'Bank Mode' I clicked to add an application. I tried adding the Faststone Capture program and a message told me "Untrusted application can compromise your secure session." It also said that the program is unsigned. The same thing happened for the VLC Player and Faststone Image Viewer. These programs are totally safe right? (Even though they are unsigned.)
Bugs resulting in security problems in video or image processing applications happen regularly and happened in the past at least with VLC too. Apart from that it is unknown from which source you got these applications so they might be infected with malware. And this can also happen if a trusted download source was compromised.
In summary: It is not totally safe and there is probably nothing like total safety at all.