I've said this in almost every grace period thread I've come across. Adding a grace period would severely hurt the gameplay. The reason the MCSG servers don't have a grace period is because it makes the game too easy. On our servers, going to corn is a gamble. If you go to the cornucopia, you may come away with nothing, or you may come away with plenty of food and a diamond. However, if you go, there is a chance that someone else will get a sword and chase you. The other option is to play it safe and not go to the cornucopia at the beginning of the game.
It's a gamble because you never know if you're going to survive the start of the game. With a grace period, the cornucopia wouldn't be a gamble anymore, it'd be an essential part of the game.