Not really. It mostly depends of the platform the person is using, and how much they care about breaking the law. I do not believe it's very severely enforced. It was, after all, made to regulate the porn produced by companies. For example, one girl I follow, Morinaga Meru, is in Japan, she has a Fantia account that complies with regulations, but that doesn't stop her from having an OF account with fully uncensored spread goodness. You also can not forget the FC2 market.
TLDR: Niku does not do uncensored mainly not because of JP laws, but because she doesn't want and need to. I mean, she only showed her nipples like one year ago.