I'd be much, much more worried by a VASL opponent who suggested using a camera and real dice over the random.org dicebot. For one thing, it would be much less convenient; for another, someone who wanted to cheat over a webcam would have a much easier time doing it than hacking random.org.
As for sharing dice... my opinion is that someone insisting on using their own dice and not sharing tends to be suspect; JR's version ("we don't share, but we can switch if you like") is much fairer. In practice, I don't care much; in theory, anyone who insists on following a protocol that would be beneficial to a cheater, is doing it wrong.