Just keep in mind that as a producer, you are looking to squeeze something magical out of your singers. You have to push them and pull them to make them feel comfortable enough to give it their all. It just seams ridiculous to me that you'd attempt to do this while simultaneously locking your singer in a closet. This kind of reminds me of that scene in Swordfish where Hugh Jackman (the Wolverine guy) had to hack into something with a gun to his head and a girl doing stuff to him. Why put the gun to your singers head? Well......actually that thought has crossed my mind a few hundred times!!
Just in case you do record a singer who was locked in his closet at an early age, there may be a chance he/she is totally content with closets and even likes them. If you can use a closet to get you closer to where you want to go, use it!
Also keep in mind that one of the easiest ways to record great vocal takes is with the singer in the control room. I've done this a ton of times. I often like it! You can really get personal with the singer. You are not yelling or talking back through some talkback microphone and headphones. You are communicating one on one. This won't work well for all singers, but for some, it's the only way.