I will also share with my friend the JADE acronym and what it stands for. I don't know, but I think it will be a difficult habit for her to break, but so necessary when dealing with her friend.
We've all been trained to give excuses--it's a deniability thing. We don't want to say "we don't like you that much," because it's hurtful.
With most people that's a good thing.
But when you run into pushy people like this, you just have to do it.
And note that my phrasing doesn't say "we *don't* like you." It just says "only this group," and it uses a group that denies other people entry without being rejecting.
That makes a great deal of sense and I will explain it to my friend the same way you explained it to me.
Slight detour - but it does relate, if you think about it.
I sew. I sew for myself, my spouse, my kids, the grandbaby, my parents, nieces & nephews, and various in-laws - when I have the time, the energy, and know that there is something that they would *like* to have made for them. I do not sew for random people.
I have been asked if I would sew something for someone (sister-in-law can't sew - they'd bought a costume in a kit for a niece). I sewed that up that evening in exchange for them inviting us to dinner because I would not have time to make dinner for my family AND sew the costume up.
BG - They had not asked in advance if I would do it - I was picking up DD from their house and niece asked me point blank if I could/would do it because her mommy "didn't know how". It was the day before Halloween...so if it was going to be ready for Trick or Treating, I had to sew it that night. I did *not* want to fix dinner at home then stay up half the night sewing (machine in our bedroom) and then be exhausted the next day.
Several years later, a co-worker asked the same question. I told her that I would sew for her if she cleaned house & fixed dinner for my family while I was doing the sewing for her - as I only had time after work to do either my own housework or the sewing. She declined to drive thirty miles to fix dinner & clean my house, for some reason.
I have several relatives who have been asked to join us at one time or another at the time share. DD & her family showed up. My parents showed up several times, with a nephew or nieces in tow. My sister has shown up. Other friends & family members have been invited but have declined or cancelled instead.
The only person who tried to invite themselves was a SIL and the mother of the nieces who had been there before twice (invited a third time - but they decided that they didn't want Grandma & Grandpa to take them because they drive too slow or some such comment [where Grandpa heard it] and their parents were not able to take the time off work to drive them instead).
Grandma & Grandpa decided to have a stay-cation that year instead of spending a day driving from their house to Brother's house, three days driving from Brother's house to Orlando, a week in Orlando, then three days driving back to Brother's house, and another day driving home. As they were in their mid-seventies at the time, I assumed that they knew how much energy they wanted to spend. DD & her family as well as VorSon, VorGuy, and I sprawled out over the three bedroom time share and enjoyed the heck out of it. Privacy for six people is better than little or no privacy for ten people...although we could have had up to 12 in that three bedroom unit...with three bathrooms.
We have asked Brother & his family about going with us - but they apparently don't plan out their vacation over a year in advance (if we don't make reservations 13 months in advance, we have additional charges to pay - so we plan things well in advance). If they want to be more spontaneous, then they can be. But we might only have a one bedroom reserved in advance and there could be no way to change that due to "no room at the inn" if they ask about joining us a month earlier.
Or we could have already gotten into the mind set of "it's just the two of us" and not want to add anyone at all - not even a grandchild.
Rather like your already planned and reservations made for a one bedroom with close enough friends that you don't *mind* sharing with them. The random friends of friends can get over it or die mad.
At this point, it might actually be easier on your friend if the woman decides to "teach her a lesson" but cutting her off for a while. Sometimes the best gift from a mooch is their absence...