If other Americans are like me, when in an unfamiliar place we tend not to read the signs so much as look around for other cues as to what we should do or where we should go. I don't know why I do this. Several times when I have visited a city, I have had people say to me, "What are you doing? Can't you read the sign right there?!" (Once, in New York City area, I drove into the wrong lane at a toll booth and a guy yelled at me. I said, "Sorry, I'm not from this area. I'm from Ohio." He responded, "What, they don't read in Ohio?!" funny guy)
As for the older lady doing that job, it does seem like a younger person would be lifting luggage. But, maybe the woman needed a job so bad and this was the job she could get. There is such a thing as age discrimination here, making it harder to get hired after a certain age . . say 50-55. She might have been told, "If you can do what the job requires, you got the job." (and if/when she can't do it, she'll be gone and they will get someone else who can).
Where I work, we sometimes have older and/or small women that have to lift things that are kind of heavy. A co-worker might help them, but basically everyone knows that if this is your job then you have to be able to do it. If you cannot do it, or do it safely, you cannot keep that job. They call it, "Not meeting the minimum requirements of the position." If they get injured doing a job, they get rehab and temporarily put in a "transitional" job that doesn't require such physical strength or endurance. But at some point, they have to return to the position they had before or they won't have a job. They can try to get disability income, but that has really become much more difficult to get approved, due to all the people who want to go out on disabiklity retirement. This is life in America.