This sounds stupid, but I already have a few Mario amiibo so I'll probably check it out anyway.

Alright, so cancel a preorder for one of the amiibo that come out on March 18 and wait a week to get it. Good scheduling Nintendo!

The EU Report:
This wasn't show at all, which fits in line exactly with what Liam Robertson said back in December 2015 before the game was even announced.
https://www.youtube.com/watch?v=N3T9ddHXVSU
"Nintendo of Europe has decided against this. Around when the promotion period ends in the US, Nintendo of Europe will make it free for everyone."

Not sure if I will buy an Amiibo just to get it sooner, but I will download it.

Unless one of the amiibo on my hitlist (Cloud/Corrin/Bayonetta) hit before the free day, I'll wait. (Or if something I'm on the fence on bombs like Nook did.)

Ha! I'm never gonna use that app. There's no content for people who don't own those Amiibo.

*Looks over at Smash Mario, Bowser, Bowser Jr., and Yarn Yoshi*

Oh. Huh. I guess... I'll be using it after all.