If a product is made to look like a branded product, a replica as such, that's fine. The problem starts when the brand id is copied as well, that then makes the replica into a fake, which is fraudulent.
You say it's easy to recognize some brand such as Adiddas and so on, in fact it's not easy at all and that's where you can get into trouble. If someone can produce an excellent replica, then they have the ability to also produce a fake. Just because the product says Adiddas on it, doesn't mean it's authentic.
When dealing with branded products you can ask for proof of authenticity from the supplier. If they are unable to provide this, then stay well clear. A simple tip when dealing with Chinese suppliers, don't buy anything at all that is branded, no matter what they say. Stay to unbranded items from China.