I transited HND yesterday without any problem.

My route was HEL - HND, HND - BKK. Both flights on JAL but with two separate tickets. Note - in this instance I would have been refused if I had check in bags as I would have had to clear immigration in HND to collect bags and re-check which is not permitted.

When we landed in HND from HEL and the aircraft door was opened all customers were advised to remain seated. Then an announcement was made for transit only pax to disembark. There were only two of us and we were met at the aircraft door and escorted to the transit security checkpoint.

From there, we were free to roam the terminal.

I used the JL F lounge which was busy although not overcrowded. All food needs to be ordered by smartphone using a QR code and is delivered (very quickly) to your table. Choices included beef curry with rice, a 'set tray' of mackerel, egg roll and pickles or a sushi plate. Drinks were self service.

As an aside I flew JAL J class and both flights were phenomenal. I was lucky to nab First Class seat 1A on the HND-BKK flight which does not sell F as well.