Had a couple people bring it up, so a memo announcement for rule clarification.
If two players make contact on the Opening Rush, they are not explicitly out. Incidental contact is permitted.
If the contact is more than incidental, the Official may deem it as Unnecessary roughness or Excessive Physical Contact, and issue the relevant yellow card to the offending player(s) [2016: 126.96.36.199.2].
Players are also discouraged from wrestling for a ball under the Possession Contention clause. This can happen at any time during the game, but is more prevalent on the Opening Rush.
[2016: 188.8.131.52.1] Possession Contention – If two players pick up a ball at the same time and neither player secures possession after two seconds, an Official shall instruct both players to drop the ball and back away towards the Baseline, then place the ball where it was located prior to the players’ contesting possession.
So, a player is not out on the opening rush unless they are hit by a thrown ball, caught out, or makes a boundary violation… normal stuff that occurs at any time in the Match. Contact with the opposing team doesn’t make either player out. Rougher contact can warrant a yellow card at the Referee’s discretion.
In Rulebook 2011 Ver 1, [V.a.ii.3.] stated
Sliding, tackling, throwing elbows or otherwise initiating rough physical contact [on the Opening Rush] will result in the offending player being removed from play.
However, this was not very specific. Some Officials called the player out and sent to the Jail, but some issued a Yellow Card for Unnecessary roughness [V.h.1.b.iii.] and the player was out for the entire point.
In 2011 Ver 2, this was updated to be an explicit Yellow Card for the offending player. In addition to actually ruling what happened to the offending player, safety reasons were the main reason for this clarification, if I recall correctly.
The current ruling for this “big” contact on the Opening Rush between opposing team members is that it may warrant a yellow card. But incidental contact is ok.