Why would my sister mind? Does anyone have sister, lol? Because she likes to be in charge and dictate what is going on, that’s why.
I always choose my kids over my sibblings, but YMMV. You could offer to help subsidize your D’s room and all of you stay at the fancier place if you prefer as a treat for your D and yourself. Depends on finances and how you feel.
However, when one is making choices on behalf of others, it is more polite to pay attention to the others’ cost constraints, unless one is subsidizing the extra cost being imposed on the others.
That ^ assumes one’s siblings act rationally. 
I would say the cheaper hotel is fine – especially since it is close enough to where she is staying that it won’t be a huge inconvenience. You can easily walk over and meet her at her hotel. Hopefully she is grateful that you and your family are coming in force to support her daughter.
Seems unanimous I’d just decide what I wanted to do (stay with my D and save some money, personally) and, if that’s what you and your H want to do, I’d just mention to my sister that we’re switching and staying at a different hotel to be with d and her bf. And, if she wants the name so she can stay there too, to let you know. Perhaps there’s a tough dynamic between you and your sister that’s hard for us to understand but, IMO, you are certainly allowed to change your original plan and do what’s best for you.
Sorry This is such a difficult issue for you. Family dynamics are often complicated. Lodging for grads is not something I even remember!
When our kids graduated from college, I can’t remember where we stayed the 1st time but my BIL and SusIL stayed at modest lodgings they liked and it was not an issue for either of us.
The 2nd time, when D graduated, I made reservations for all of us at an over-priced place across the street from campus. The convenience was nice but it wasn’t our favorite stay. There was no drama and it was easy.
When I went to my niece’s graduation in SF, again can’t rememver where I stayed, it was a nonissue.
When we went to my nephew’s graduation, my brother was pleased he got a great deal bidding on HotWire or Priceline. I begged him to get me a room too and he bid blindly and did but it was a different hotel from his. Both hotels were nice and only a 5 minute drive apart or so. It was fine—our kids stayed with us in our suite and his with him in his. I think we paid about $50/nite, including breakfast and free parking and internet.
I would still hold firm that you to stay at the same place as your DD and that she cant afford that hotel.
No one is “alone” at a hotel unless it’s otherwise empty. And seems Sis will have her 17 y.o. with her.
Do what works for you.
I’d stay near her only if you’re so close and expect a great girls night, but that doesn’t seem to be the picture.
This is the text I just sent my sister, she is notoriously hard to get ahold of so I decided to text her right away.
So D is coming to graduation and bringing bf but she just couldn’t swing fancy hotel. So she made reservations at cheap hotel. Here’s the info on cheaper hotel. It’s near major landmarks but is a 30 walk to fancy hotel. Wondering if you would want to switch hotels or do you really want to stay at fancy hotel? I’ll do whatever you want but it would be nice to save over $200.
As far as location to graduation, neither hotel is near campus but in the middle of the city. We will have to Uber to graduation site with either place. Sister wanted to stay in the middle of town instead of near campus.
I think my sister should be happy that D is willing to come to graduation. It’s still costing a bundle.
@deb922, you are very gracious to sis! I thought it’s only a 15 minute walk between hotels but now sounds like 30. Hope she responds in a timely banner do you can finalize plans.
I was mixed up, I think there is a subway stop between the 2 and that would be 15 but a 30 minute walk. I got confused when I was talking to my kids yesterday. Common occurrence
Your text sounds like you’re leaving the decision on your hotel up to your sister? Was that intentional?
Yes it was intentional. I will stay where she is, if that’s what she really wants but she needs to understand that D can’t afford it. I’m making a gamble and hoping she will decide that it’s better for all of us to stay at the same place. I was feeling guilty that she made arrangements but then i am changing them. Actually it’s not me but D.
Heard back from my sister. She feels bad also but cheap hotel is not near many bars and restaurants and we would be paying a bunch in taxis and Uber’s. So Im going to stay at fancy hotel. Now I know though.
D will be fine, she can hang with us and will probably only sleep at cheap hotel.
Thanks for everyone’s advice. I’m glad how I worded things. Sister is going to look for a cheaper hotel in the area she says is better to stay at.
Good outcome!