That’s surprising. Elevators do require key cards to operate, but I would always sneak in with other guests as if I had booked a room there
A valid explanation could be that
@Anna Summer and I never encountered problems simply because we are foreigners and receptionists assumed we are guests staying at the hotel.
If you stay at Shinagawa Strings, meet your lady on the ground floor of the building complex. (These complex buildings have leisure & shopping facilities on the ground floor, offices on the bottom half of the building and top floor are usually reserved for hotel area.)
This topic has been discussed before many times, and nowadays I’m in quarantine but here are my top favs:
Winners: Aman (amazing floor heated bathrooms with a city view) and Andaz
Runner ups: Peninsula, Park Hyatt, Shangri La, Mandarin Oriental, Ritz Carlton, Grand Hyatt, The Prince Gallery (transparent bathrooms
)