My opinion this is a dog and pony show as usual. Untwist your panties, take a deep breath, have a beer or whatever. These people are after the big money, not the skint foreigners. Can you imagine the turmoil if you bring in your home country tax return for these folks to peruse. Even I don't understand all of it which is why I hire a tax professional.
For this to work the Embassies of all nations needs to be a part of this to help with paperwork.