people experiences will differ because they apply at different embassies. Those embassies decide what they require. So if seeking an answer you'd have to post the question to include which embassy you are applying through.
It's 72 hours from day of arrival. You know what day you land, just count back from there. You can fill it in even on day you arrive, before you pass immigration.
yes, it's the age old "blame the foreigner" malarkey. I get stupid trolls posting offensive stuff because they think my name defines nationality. Mostly yanks, sad to say. But as a British person with the birthright and DNA to prove who I am, it's just pathetic.