Thank you, everyone
I'm glad someone thinks I'm a sweetheart.

I am not trying to please Dora. I don't care if she likes me or not other than the fact that I do have to work with her regarding the care of another family member and she can and has tried to undermine my relationship with the other person. I try to be civil but I have as little contact with her as possible.
I guess I feel guilty about not liking her because I do want to be a gracious person--but that doesn't mean I will be a doormat or an ATM. I do have boundaries. I feel guilty for not liking her, but not for withholding FF miles. I have no intention of enabling her mooching behavior. She is a spoiled child in a middle-aged woman's body. She does have good points (I'm trying to be balanced here) and I think she is suffering from her upbringing. That's not my fault and I'm not going to be her mommy.
I just find it so disturbing that she would even think to ask. I just don't get that kind of entitlement attitude. Yes, I have more than she does and, yes, I do feel that where much is given much is required. But that does not mean being an enabler. I give to legitimate charities and I do not consider her vacation plans to be a legitimate charity.
Yes, I believe family should help each other but this is not helping. At least she is not asking me to co-sign a home loan.

I should count my blessings.
I think I am just very, very disturbed by her attitude and behavior. What next? I wonder if she has a mental problem.
As for why I want to be tactful, it's because that's the kind of person I choose to be. I don't want to fall to her level. It isn't for her benefit. It's for mine.