It contains no user serviceable parts...Read the fine print..opening WILL void your warranty...Leave it to Apple, if you have your Mac in a case, interior dust should not become an issue, particularly in such a new machine.
I use a Speck clear shell on my MBP and my MBA, I just take them off once a month and clean with a micro-fibre cloth.
It would come down to whether or not they can tell it's been opened. Note that they're using pentalobe screws on the bottom. These are used by Apple for non user serviceable parts. These are anti-tamper screws. If you strip them with a cheap driver, it's possible that it will be difficult to get your machine serviced. If you went past pentalobe or triwing (Y-type) screws on your prior macbook pro, that was no different. Anytime you see anything beyond phillips, slots, or torx screws, it's not meant to be taken apart by the user.