Hi there Vicki74,
I can see that being able to block a parent account's use directly in transactions is a feature that you'd like to see to make sure your transactions are entered correctly. I recommend leaving Feeback in the system by clicking on the Gear icon, then Feedback. The comments made in that section are taken into consideration by our developers when designing new features for QuickBooks Online.
If you have any other questions, feel free to reach out here.
