Newbies in the climbing room were teaching other newbies how to use a figure of eight descender as a remote belay device.
Want to know how they know how to use it the wrong way, because everyone does. As you know if everyone is doing it then there must be some truth in it.
Same as with a Petzl Gri Gri. Ladies and gentleman, do not trust anyone except your closest friends, with whom you can communicate clearly with, to belay you.
When I am talking about communicate, I mean being able to tell them that stand 25 feet from the wall to belay is bad and holding onto the rope coming out of any belay device and being able to lock it off in any position they happen to be in is the only way you want them to belay.
When you can communicate this and consistently see is happening, then you can climb harder than what you might solo.
Before that time, take it from me. A Korean dynamic belay is just that. The dynamics are beyond belief!
This is the voice of wisdom, and experience. Just cos every one is doin it don't make it the right way.