Well done you. I totally agree. I know people leave their dogs at home and ask someone to come and let them out for a wee etc, which I find totally unacceptable and something I couldnt do.........but on the flip side, if the dog is so old, is she better at home and somewhere she knows, than being put in kennels? I have a friend who runs a boarding kennels and time and time again she has had old dogs left for boarding for the first time in their life, and they have become really poorly, unfortunately two have died in the last few months, and she is now refusing to take them unless they are used to a kennel environment and in good health.
I know you will worry about her when you go away more than her owner will, but at least you gave her a nice week.