Random Obsevation # 028

In most of the places where there is a lawn, you will see a board that says "Do not walk on the grass". Observe closely and you will realise that:

1. The sign would invariably be in the middle of the lawn. If one had seen it along the border, it would prevent them from walking on the lawn. But since its in the middle, one wont realise the mistake until they actually start walking on the lawn and reach the spot where the board is placed.

2. Since the sign is in the middle of the lawn, how did it get there? I once saw someone walk on the grass and fix the sign there and am pretty sure that all signs are placed using the same strategy. So how does that person come back after placing the sign, since he now has to adhere to the policy of not walking on the lawn?