Frankly I feel all the wise-crack remarks regarding seniors are a little out of place. The fact that Seniors can pay or not is irrelevant. When a discount for seniors is offered usually is an advantage for both parties because it is easier for seniors to visit a museum or go to a movie during working hours. On the other hand when someone is retired most likely has to be more careful with its fixed income.
When a hotel offers a better rate to any group or person it is simply because it is good business for the hotel. Same principle.

flanneruk--There are a lot of American (and other) seniors who do not have vast unlimited incomes and who, because they would like to see more of the world than their own backyard, scrimp, save, and (like me) work several days a week at a low-paying job in retirement just to be able to afford such trips. In my case, every little bit helps (espec. considering that everything in Britain is approximately twice what it is in the US) and I don't feel like I'm taking advantage in the least by getting these discounts. If they had a problem with non-British getting the discounts, they would limit them to British citizens. Obviously there's something in it for them too or they wouldn't offer it so freely. We aren't twisting their arms to get concession rates.