We found this written instruction attached to the toaster in the morning of Saturday January 3 in the restaurant of the hotel where we stayed for ski/snowboarding tour.
There were three young Australians working as catering staff at the restaurant, so we asked them about the notice. But none of them knew what it says -- "For foreigners". This note could be shocking for those who can read Japanese (kanji).
One of the participants from the US posing with a sympathy to me: "Oh, you are a Japanese, and so you are not suppose to use it."
The majority of the participants of this tour were foreigners. Even though most of them have been working in Japan, they still have a difficulty in reading kanji, and so most (all?) of them did not notice this written note until I translated it for them. On hearing the meaning, the foreign participants and catering staff started to laugh at it by saying "what's the point?" The notice written with kanji was incomprehensible to them, just like one of many enigmatic notes in Japan. Maybe it was meant to Japanese guests to prioritize foreign guests to use the toaster. But we could not spot any other toaster (the one I could use) in the room.
Next morning, we found another toaster at near the corner of the large restaurant. This toaster did not have a note showing any segregation message, so I should've been able to use it. The other toaster still had the note of "For foreigners." -- it was not removed after I translated it for the staff a day before. Probably it was an innocent act for the restaurant to put such a note without realizing its implications -- Japanese hosts are still on learning curves.