I dont see the point of a 30 man sqaud, unless the selectors dont want to offend someone, just being wusses. Why not name a 100 man squad.
I think it should be a 20 members or less or less squad. So everyone who is there knows they have a realistic chance of making it to the team, and the message to everyone else is, you are not good enough so try harder.
In case of injury if there isnt a replacement available in the other 19, another player can be included.