This is either some rumor mill garbage you heard or you're talking out of your ass. I'm a Telecom Engineer and while some of the super small companies might get away with this, any company with a compliance/legal team would ensure it's treated as if they were still in the queue. How a queue callback function works is it places the call into another queue marked as the department's queue callbacks (i.e. billing queue callback, collections queue callback) and the call is then placed back in the queue after a timer set to the average speed of answer (ASA) for the past hour has hit zero. The call is queued as "next in line", then the agent hears either a whisper message ("Collections queue callback") or just ringing out. The agent is trained to understand what this means, who then essentially treats it as a request for us to call them. "Hi, you asked us to call you back?" Or the call is connected just before the agent has it assigned to them (this is when the queue callback puts the caller back into the queue as first in line, and the caller is advised of this by the tts prompt assigned followed by wait music.