That is part of the problem that bugs me, big hatcheries label Easter Eggers as Ameraucanas. In small print they say they are "Easter Egg" type chickens. So, people buy them under the premise that they are in fact, Ameraucanas. I have Ameraucanas, I also make/have Easter Eggers, so when people ask me if I have Ameraucanas, I always clarify what they are looking for and 9 times out of 10, they are going to be Easter Eggers. It is hard to explain to people sometimes what a purebred is even, then to explain the difference between these can be like banging one's head into a wall.
We can't be 100% certain what color a bird is going to produce when we cross two breeds who lay different color egg genes, but we can come pretty close when you know what both parents are carrying. To make Easter Eggers is pretty easy though, you take a rooster who carries blue egg genetics (there have been discussions lately about it not really being a gene but something that attaches to the genetic coding that influences the egg color, which I still feel is genetically passed), and put that rooster over a hen(s) who lay either white or some shade of brown, and you should get blue or some shade of green from the offspring females. That is how so many people are able to sell Olive Eggers now, take an Ameraucana rooster, put him over Marans or Welsummers and your offspring females should lay an olive color egg. Now, I have olive eggers that I don't know how they got that way for sure, but I don't really care because I don't sell them as olive eggers, all of those crosses are sold as Easter Eggers.
Here is a fun little cross, I have a little barred hen that was supposed to be an Easter Egger a couple of years ago from eggs I bought from a breeder. She lays light brown eggs. She is a bantam too. The only bantams I have are Silkies and Salmon Faverolles, so I put her in with some of my bachelor bantams. She started with just a White Silkie rooster. I have started hatching her eggs and the offspring are just cute as can be, and some of them are barred like their mom, but I think all the barred ones are males, unfortunately. They still have 5 toes but they aren't as silkied in their feathers, and they have black skin too. They are cute and some people just want bantams and don't care what kind they are, so I thought they might be a fun little deal to have around.