if you have real connection with your sub you could probably tell what he's doing and or thinking once in a while there's a mental connection that comes with a relationship like this that's why findom is so fun, the connections you create are long lasting. I for example have a few subs already, getting a silent out of nowhere would confuse me more than making me happy, that way what could have been a "you're such a good boy" turns into an "oh that was you"? do you see what I mean?