It just seems unlikely. I suppose it's not impossible, but in my experience robocalls start immediately. And maybe it would work if you pressed "mute", but with

It just seems unlikely. I suppose it's not impossible, but in my experience robocalls start immediately. And maybe it would work if you pressed "mute", but without that, you'd leak environmental noises into the call. (People talking around you, cara going by on the street...) It might just be a trick that people pass along regardless of effectiveness.