I am sometimes on the receiving end of this "silent" technique. I hold eye contact for as long is appropriate and then turn around and sit at my desk and start working.
On the other hand I went to return an unworn item to a shop and they told me they don't refund. This is against the consumer law, which I told them. They said they would have to clear it with head office and I would have to wait. I said, fine, I would. A bit of phoning back and forth commenced. I waited patiently. As soon as they had cleared my cash refund, I told them I would take something else.
Hehe, some people are immune. The art is knowing who will crumble. To be fair it hadn't failed yet. I think when you don't speak out often makes people desperate to break the silence!
I'm immune ;) ... but I know what you mean.