Technically, SA
did break a safety rule. According to the Guest Conduct Policy passengers are no allowed to sit, stand climb on or over any of the ship's railings, not just the exterior ones. From the policy statement:
Unsafe Behavior
Sitting, standing, lying or climbing on, over or across any exterior or interior railings or other protective barriers, or tampering with ship’s equipment, facilities or systems designed for guest safety is not permitted. Guests may not enter or access any area that is restricted and for the use of crew members. Any other unsafe behavior, including failure to follow security instructions, is not permitted.
https://www.royalcaribbean.com/content/dam/royal/resources/pdf/guest-conduct-policy.pdf
Also, I learned that railing heights are 42" - I'll try and find the source again. The railing not only serves to help steady people in choppy seas but also to keep them a safe distance away from the windows. To me that alone indicates a safety feature and shouldn't require an additional sign saying to keep a safe distance from the windows. Or that the windows may be open. IOW I believe RCCL did their due diligence in keeping the passengers safe from falling out open windows.
And finally, after much thought I don't believe SA's color blindness made any difference in his inability to know that the window was open. The railing is about 10" - 12" from the window so not very far at all. The video showed that he leaned forward to see out the window so he had to have been no further than 5 or 6 inches from the open space.
IMO if he couldn't tell the window was open then something else was in play. What it could be I don't know. All MOO.
I'm a few pages behind so apologies if someone else has mentioned this.
ETA: And sure enough I just saw that
@oviedo has already addresses the ship policy.