This may be true in newer cars, I am not familiar, so I'd definitely take it into account.

In my old sedan, a 76 impala, the parcel shelf is basically cardboard.

It has rotted dramatically over the years from sun and moisture damage, and now that the car is re-done again, I will be getting rid of it, period.
I would never recommend someone permanentely damage their car structurally for a setup, obviously.

So take Salty's advice into account for sure!