As someone who discovered firsthand that karaoke microphones make good fomites (someone shared a nasty cold with me once, by way of a karaoke mic), I'd like to point out that this is a Very Bad Idea. --All the more so, since a lot of the karaoke venues in Japan include smallish private rooms, where the ratio of students to square feet (and, therefore, the opportunities for large droplet spread) can be quite high.
Is this an argument for not shutting down schools, then?
Probably not.
Unless a very high percentage of students from these closed schools are crowding into the karaoke joints or other venues where there is a relatively high risk of transmitting the flu, school closings are still likely to be more effective than not in slowing the spread of the virus.
