This is only step 1. Step 2 is to ban people from installing unapproved apps on their phone. But, as you say, these apps are just a few lines of code, so step

This is only step 1. Step 2 is to ban people from installing unapproved apps on their phone. But, as you say, these apps are just a few lines of code, so step 3 is stopping people visiting non-whitelisted websites.