Priests confess to other priests. When you are behind the screen, a priest generally doesn't know who you are.
Greetings...a respectful observation...if one is behind a screen I fail to see the "difficulty" in confessing one's sins? To me speaking anonymously to a priest would be much easier than to ask the Lord God Almighty directly in prayer for forgiveness. I can't hide anything from him, but in a confessional I can speak to whatever I want to (Granted I would know that I am hiding sins from God--see the effect here?). Ultimately in both cases it is God who I am confessing to and to try to hide anything from him is unwise...Clearly the most important tenet is to confess of the sins we commit and do our absolute best to avoid sinful behavior in the future.
Blessings in Christ!