Hi there Knotties!
I'll try to keep it brief.
Short background: Myself and bridal party (1 MOH, 2 BMs) all live in SoCal. We were (still are) planning on going to Vegas for a weekend of bachelorette shenanigans (yay!). One of my bridesmaids turned up pregnant, and is due a week before the wedding in August. The trip is planned for July - hot, hot, hot - meaning the pregnant BM doesn't want to go, for which I don't blame her one bit. This has opened up a spot in our room, with the count going from four to three. We all agreed that, in addition to being a bachelorette, this would be a nice chance to have a girl's weekend away from kids, husbands, work, etc.
To present: My MOH and I had previously discussed inviting other ladies that I'm friends with, and I said I would give it some thought. Maybe MOH's sister, or my old roommate (finishing school in the SF area) would want to go. So far we hadn't set anything in stone, except for booking the room.
I touched base with my old roomie, and she expressed interest in flying out to Vegas for the trip, while the rest of us would drive. Unbeknownst to me, my MOH asked one of her best friends (I went to high school with her but haven't spent any time with her in the last seven years, and she isn't invited to the wedding) along with MOH's sister if they'd like to go without discussing it with me first. Her friend said yes, her sister is still unknown but not as big of a deal because she is invited to the wedding and in all liklihood wouldn't be able to make it due to her financial instability. She said that she (MOH) and her friend would be willing to sleep on the floor of the room. For three nights. In Vegas. That it would save us some money on the room (which, with four people for three nights works out to be $110pp for all three nights in a hotel on the strip - not bad by my standards).
You see, my MOH and I are at different stages in life - I've got a one year old with my FI, we've been together for eight years, both steady jobs, don't party much anymore, etc. while my MOH will still take off on vacations with friends on a week notice, and is willing to sleep on the floor of a Vegas hotel room to shave $50 off the hotel cost. This by no means makes her a bad person. I love her, obviously, she is responsible enough for me to ask her to take on the position of MOH. While I know this is my bachelorette celebration, and I have a right to say who is and who isn't allowed to attend this event, I'm at a loss as to how should I go about telling her I don't want her friend to come without hurting her feelings. She has done a lot thus far in terms of helping me with planning, meetings, etc. and I don't want her to feel like I'm just casting her suggestion to the side. However, I don't think the other girls I've invited would appreciate stuffing six girls into a room meant for four for three days.
It ever-so-slightly seems as though she is trying to save on the cost of the hotel. I made it abundantly clear many months ago that if anyone didn't feel like they could swing Vegas, that we could absolutely and happily do something else locally to spare them the cost of going to Vegas. Everyone was willing and raring to go. I checked with everyone once, twice, three times that they would be okay with it.
Thanks in advance for any advice.
Update: BTW I'm aware that a bride planning/helping to plan her own bachelorette in some way breaks some unspoken etiquette rule/taboo, but whatever. I don't feel like it's right to just leave everything up to the bridal party. Thanks again.