As long as the consumer is informed it isn't unfair at all. Yes, it adds to the total cost but that doesn't make it unfair, just like the need for memory cards when buying a Vita (non-issue today because the new model comes with memory, I think) or the exclusion of batteries for electronic products isn't unfair. It can be annoying for sure but that doesn't make it unfair.

US or no? Just curious.

My iPhone 4s and both iPhone 6s came with both lightning cables and the wall adapter (little white box with the usb slot). Wondering if this is possibly just a US thing to always expect stuff like this in the box. 

I am US.  Got my wife an iphone 5s back in April and it had the lightning cable but no wall adapter.  The two Samsung phones I purchased this year both had wall adapters as well as the cords.  I think a lot of companies are flirting with the idea of removing some of these items, especially as they continue to get further saturated with upgraders as opposed to initial adopters.

Something must be wrong or maybe they tried it and failed, but the usb wall adapter is supposed to be included in the box. Apple even lists it as part of what's included.

http://store.apple.com/us/buy-iphone/iphone5s

Pretty sure, in the US at least, Iphones come with both the cord and adapter.  Don't know about your situation.

I don't think anyone is saying they will be legally liable for anything, but that doesn't mean they can't be criticized for what people see as bad decisions for consumers.

In a way this could even be a good thing, because it teaches lazy people to inform themselves about what they're buying.
Learn2ReadUImbecile, part of Nintendo's QOL program.

Entirely possible they just gave me a box that they were using the ac adapter from for the display piece or something similar then.  Funny though, at the time I just assumed it was their way of cutting costs.  Also, since we already have 4 chargers from Apple, didn't think it was a big deal.  I just changed out one of the older cords with the lightning cord on an adapter and off I went.

And still there are plenty of people defending this. Keep on defending the company that is exploiting you more, it will be interesting to see how far they are willing to go and how far you are willing to let them... But please, do continue pointing out flaws in companies you do not like...

A festive quote for all:
"In Germany, they came first for the communists. I didn't speak up because I wasn't a communist.
When they locked up social democrats, I remained silent. I was not a social democrat.
Then they came for the Jews. I didn't say anything, I wasn't a Jew.
And when they came for me, there was no one left to speak out."
Martin Niemöller

I thought about that earlier but didn't want to be the one to say it.

That's not exactly what they're doing.  They simply expect that, from now on, the majority of New 3DS owners will be coming from previous 3DS/DSi owners.  They probably expect some growth, but not enough to care about including an AC adapter.