You have an interesting way of looking at things.
Let's see what SDM wrote in the title post:
It's a very small crack which also set off the Pedestrain Saftey system, where the bonnet pops up. It's a one use system
Pay close attention to one use system. Just like an airbag; when popped, you have to replace it. But if we follow your suggestion, we should just wrap the airbag up, stuff it back in the cavity it popped out off and then close the cavity with some adhesive.