Problems With Open Mic Policy

I have been in church's were they pushed prophecy and some even let just about anyone come up and speak in the mic and it was not good it often killed the spirit and cause some visitors to never come back. More so if the visitor was ask to stand give there name and then be given a prophecy. I believe in prophecy if it is done in a right way, But I also don't believe in an open mic for the church service and expectedly on Sunday service.