Putting a label onto a product is there for a definite purpose, it informs a person what is in the container, so it is pointless if it is going to fall off when faced with certain conditions such as varying temperatures or water for example.
A bottle of shampoo is very likely to be in contact with water and food may well be stored in a freezer for example, these products will have to have label which will withstand these conditions, stay firmly attached to the item and be readable.