I'm going to suggest my girlfriend not pay for her sister's vacation. Think that is wrong of me to do?
Why don't you want her paying for her sister's vacation?
I hate the bitch and I want to rub her nose with it
If you dont want your girlfriend to pay just because you don't like her then that is wrong. If you feel it is the right decision because your girlfriend is enabling her then you have more of a point with that.
Since you agree, I'll let her know. I'm happy.
I just think it's best to stay out of the whole situation. You will only cause issues getting involved in their family issues.