Unreserved Reserving

For all Japan's lovely traditions, including the practice of cherry blossom viewing, one thing that annoys me so much is how far people to go for basho-tori, or reserving one's space.
At the big parks like Inokashira, there is more of an unspoken understanding that any space taken needs to be manned at all times, so you have designated people in sleeping bags overnight. This shot, however, is from a Saturday afternoon, and I assume it is "reserved" for the Sunday, which is not going to rain. My wife just wanted to rip the thing up. If I see the people who did this and it turns out that they indeed stopped other people being there for a whole Saturday just to save a spot for Sunday, words will be had.