Judging by an [exit photo here][1], you're right. When there is an opening in the fuselage (e.g., where the emergency hatch would go) the surrounding area needs extra strengthening. Below is a high-res example for an Airbus fuselage: [![enter image description here][2]][2] ([source][3]) Notice the extra and deeper [stringers][4] to the left of the door, and the lack thereof away from the door where the windows would be (yet to be cutout, but you can make out one). [![enter image description here][5]][5] ([gettyimages.com][6]) And here's a CRJ700 fuselage (first fuselage actually). While that's the front door, not the overwing exit, note the white stringer above the first window to the right, and lack thereof for the rest of the windows (its depth is clearer on the left by the shadow it casts). A sliding hard blind doesn't disappear, it needs to go somewhere. They typically go into a hidden tray, which takes space. Here is an [example][7] from a [McDonnell Douglas patent][8] from the 70s. An upside down unit flanking a hatch could very well be installed that way to make way for a structural element, or to make way for cables/pipes/tubes in the area, especially that the CRJ700 is a narrow plane. [1]: https://media-cdn.tripadvisor.com/media/photo-g/960x720/16/98/fe/52/seatguru-image.jpg [2]: https://i.sstatic.net/UUxt5.png [3]: https://www.ruag.com/en/products-services/air/complete-fuselage-sections/airbus-a320/rear-fuselage-section-1819 [4]: https://en.wikipedia.org/wiki/Longeron [5]: https://i.sstatic.net/j6neS.png [6]: https://www.gettyimages.com/detail/news-photo/the-first-fuselage-for-the-new-bombardier-aerospace-crj-news-photo/830077878 [7]: https://i.sstatic.net/VMASh.png [8]: https://patents.google.com/patent/US3691686A