Getting competitors together for a round with only each other to talk to only helps communication. We already have "Watch out for scramble 2. It's insane!" Isolating them together only encourages this possibility more, even if it's explicitly forbidden.
It's really another article, but how about saying (like in contracts) that by beginning an attempt, a competitor agrees not to have had previous communication about the scramble?
(Though, what happens if someone shouted to you: "GREEN X-CROSS, scramble #3! 4 moves!" Is that communication?)
Also, what about, say, big cube and multi BLD? If competitors go at different paces, you'd have to force them to go back-to-back (so they can't leave to relax a bit, 'cause they could obtain scrambles...
Chris K. already mentioned it, but if we're using RFC 2119, 7g should use "may."