Hotels and contact tracing tourist app

Will tourists, because of the contact tracing tourist app in the future, need to book a hotel obligatory? Because it seems we need to leave contact dates of the accommodation in the app or the visa.

The problem is that I would stay at my in-laws' house and would not book a hotel. So I cannot enter Japan as a tourist when tourists are allowed in?

Speculating on future requirements is just that, speculation. There may not even be an effective/compulsory contact tracing "app" and it is unlikely that the Japanese Government could force/require visitors to use a particular sector for accommodation (hotels versus homes).

This is purely speculation, but if such an app existed and you are required to use it, I would expect you would need to put down your in-laws home address and a contact number for them since they would be your accommodation.

Unfortunately it's too early to speculate what the conditions will be. Let there be some speculation that borders may open before discussing how it may occur.

Just as an additional point, when I travel currently (not often), there is not a tracing app or requirements at hotels. I don't see one in use currently, and even with the now discontinued/suspended "goto" travel campaign there wasn't one. Other countries encourage tracing apps, even for things like visiting shops and restaurants, Japan seems to be a long way from that. But it is also a long way from letting people into the country as well.

According to my understanding, foreign visitors to Japan - until the recent closure of the borders - were already required to install Japan's COVID-19 contact-confirming app which fully protects the user's privacy. However, I can't imagine that a tracing app which shares the user's position with the government or the like would ever be legal under Japanese law.