That's the customer's problem, though. This is just like the annoying windows popup that asks if you're sure you want to do this thing that could mess stuff up... Actually, you're not allowed, because we assume that you don't know what you're doing. ...
I'm one who had no problem with Walmart. I went to the store because I wanted to set up service the same day, otherwise I probably would have ordered sim online. I just asked if they sell sim card for PM, they said yes, said they had to do something ...