Especially when it's slippery and when you are a bit heavier it's very important to have good shoes. Grass can be slippery in the morning when it's wet. If we have nice light wind at the start it's all less important. You could start on any shoes then. In strong wind again it's better to have good shoes with profile. If your shoes are completely white and clean we cannot guarantee that they will stay clean. Grass tends to give of some green coloring. But usually it's OK. Don't forget to tie your shoe laces well: it's not the first time that somebody looses a shoe at the start (usually we get it back haha).