Well- I bet this trip into town was her one big event. I would also bet some dementia is in play here. She also maybe frustrated she can not see things for herself. My grandmother had altizmers- and later died from it. In the beginning, she was quiet and never asked anything of anyone. She also didnt have food in the house, needed necessities etc and finally when my parents discovered this fact, they moved in with her to care for her. After a few months, they had to sell the car. They tried to hide her car, but she would leave and go driving- one time got lost for 8 hours as she got caught on the 495 beltway loop and drove for hours as she could not remember which exit to take with the changes.
Older people are hard. Sometimes a little kindness reminds them of a simplier time. Some older people the reminder of kindness makes them upset- as they remember people that have left. I found when I had a retail store, if I approached a person of such needs ( and by law- of resonable accomindation, the management must comply) to fill the needs, but not going over board made them feel less embarassed about their situation. You do not know if a neighbor put her chair in the car or helped her. I understand your vent, but maybe she only comes there because your store is the only one that will totally accomindate her needs. Or she came there to have the opporturnity to actually talk to someone. If she lives alone, it IS a very lonely life. This was probably more of a day out than anything. And remember- she could be on a very limited budget- and embarrassed on that as well. If you knew her name and address, maybe social services could help.
I understand your vent- I just thought I would offer the opinion of the other end of the scale. Frustration can make people rude. And asking for things maybe her way of feeling like she is in some control of something in her life.
And for the comment of being 80 and at her age "she may not be a problem too much longer".. - put it this way- all 4 of my grandparents lived well into their 90's, and great grandparents my dad's size over a 100 ( 104, and 102) .. True her own actions could be why she is alone- or not- and that is why she is so demanding. I think she just wanted to feel like she had some control in life- dementia if at all or not- that is what I am seeing.. At least you could come here to vent- she doesnt have anyone to vent to.. Count your blessings..
BTW- I LOVE THAT STORE! I always spend more than I thought I would.. lol. I always find things I didnt even know were available... lol.. ***