Here's the article I was reading when I saw your post. It's more about non-phone devices connected to cellular networks than phones themselves. The author seems to strongly imply that while the same standards for certification apply to phones, they aren't enforced as stringently due to the profitability of selling phone service. (Presumably that's vs. a tiny data plan an online device would use. So I suspect that a network wouldn't disconnect your major brand world phone that your were paying to use on their service unless it was seriously misbehaving. But all that is my speculation, and not a fact of any kind)