I’m not sure why your friends are paying that… Most cities in Saitama, Chiba, and the 23 wards at least I know that the 学費 was set as 無償化.
There are some instances where you don’t qualify for free school if you make too much money. (Or it could just be they didn’t have a good guide at the city office to walk them through the maze of beaurocracy)
Also 23 wards and most of the cities in Saitama and Chiba have daycare and kindergarten entry that’s points based(the larger cities have more kids than daycare spots, which is my favorite bit of irony about the Japanese birthrate problems), the more points you have (points based on need, like are you a single mother, both parents working full time etc.)
I mean DMA (direct memory access) devices are only like 170 bucks now:
https://www.dma-cheats.com/dma-cards
These are almost impossible to do anything about even client-side because they operate on a hardware level.
In general state-reading hacks (like invisible walls and Gameworld state information hacks) are almost impossible to do anything about, to the point where when companies are able to find a way to defeat one of these things it’s huge news.