Friday nights tend to be really busy for love hotels, especially Shinjuku and Shibuya, for various reasons best not discussed on FT. In addition, love hotel beds, even though they are king size beds, won't fit three people sleeping, as there's only one bed per room. Also some love hotels don't allow you unlimited in/out privileges. You go in and you don't leave until your "business" is done, or you can prepare to pay for another room. That being said, some high end love hotels have those open baths and fancy bathrooms and what not.