Y.E.S. Absolutely, 100%, yes.
Do not, under any circumstances, invade the privacy of your children.
Because here's the thing - kids are people too. Kids have complex emotions, they want things, and most importantly they are still learning. Learning from their parents and other adults in their life, particularly.
Guess what happens when you invade their privacy by doing something like reading their text messages? Those kids a) start to develop anxiety and b) learn very quickly how to hide things. They get apps that will delete messages within 30 seconds of being read. They start hiding everything because they want, and deserve, privacy and now know they aren't going to get it without being secretive. And sadly, that's how you raise kids that are mentally broken, get really good at lying and hiding stuff, and never open up to parents about anything.
Your children are people, respect them like it for gods sake. Knock before entering their room and actually wait for them to say it's okay. Ask to read their texts if you're really concerned, but don't get pissy and think the worst if they say no and for the love of all things good in this world do not get angry at them over what you read. If you have a concern in something you've read in their text messages after asking permission and being given it, bring it up in a calm and adult manner and help them understand why that thing is of concern to you.
Sometimes your kids don't understand, and that's okay. Sit them down, talk to them like adults, and bring up any concerns you have. If they say no to you reading their text messages ask why and be understanding about it, don't get defensive and say you have a 'right' to just because you're paying for the phone. You chose to have a child one way or another. And as it was once told to me "If you wouldn't do it to your own parent or a best friend the same age as you, don't do it to your kid."
Yes, of course this is wrong. Because everyone has some personalized massage. Nobody should show them. We all know that parents do everything for our good. There are some things that they should never do. Many parents have those who do them. There are many parents who never do them.
I'm discussing below why parents should not see the kids message
First of all I would say that it does not have the right to see it as its personal message.
Secondly, I would say that seeing the messages parents can be more shy. Because maybe her friends have sent some messages to her where there was some bad picture or language.
Thirdly, I would say than, kids may get very sad.