Modern day Earth... the offices of state and national leaders, and mainstream news media outlets in an unspecified western democratic nation each receive an ornate, very official-looking and unthreateningly-worded letter from the queen of a nation that none of them have ever heard of, notifying them that the nation which the signatory represents will be appearing at a specified place within the borders of the real-world nation at dawn on a specific date around two months in the future, and will remain until midnight of that day.
The letters cordially invite the government leaders to take appropriate diplomatic, customs and crowd control measures, and invite the news media to send journalists who will be permitted to enter the unheard-of nation and report upon whatever they wish. They also state that the general public of the real-world nation will be permitted to enter the unheard-of nation and nationals of the unheard-of nation will be permitted to depart with minimal restrictions, unless the local authorities choose to impose restrictions on entry and exit of their own.
The letters give the address of an unremarkable middle-class home within the borders of the real-world nation as a return address (clearly not the location at which the mobile nation is set to appear), and offer the government/news media a locally-registered mobile phone number as a contact number for the queen of the unheard-of nation for the recipients to make contact, not for the purposes of public dissemination.
The question: What response, if any, are the addressees of these letters likely to give to these seemingly ridiculous letters? Are the staff of the government leaders likely to simply discard the letters, or would they be forwarded to the leaders to whom they were addressed? Would the leaders take any action beyond laughing? Would the news media send journalists?
At the date, time and place specified, the small, previously-unheard-of nation magically appears as foretold by the letters in a place within sight of a major city's central business district, and does not offer any harm to the host nation, seeking only to trade peacefully, but also being prepared to defend against an attack should one occur.
What official and media response can be expected after this event?
What response could be expected after this event should similar letters be received by leaders and media outlets in another real-world nation announcing the future arrival of the magical nation within the borders of their nation?