I'm sure they do. But that doesn't make it the right thing to do. Apple makes it very easy for parents to share content with their children with Family Sharing --> Family Sharing - Apple
Stop sharing an Apple ID with your kids. Each person needs their own unique Apple ID. If your kids don't have their own iPhone, Apple has you covered there as well --> Set up Apple Watch for a family member – Apple Support (AU)
Until you do this, whoever you are sharing your Apple ID with will have access to your content. That means your text messages, your email and anything else you'd prefer no one but you has access to.