Should I shoot for them? Feel like they don't value it

Hello all,A friend of mine has a sister that is getting married. She asked me to do a staff a "photo booth" of sorts for them. Essentially I would put the camera on a tripod, and take pictures of people in front of a backdrop.She didn't offer to pay at all to start out with. She has a photographer for her wedding, but, of course doesn't want to pay for this. Already crappy but okay maybe I can do it. Then she said that she can give me food but maybe not a chair. Huh?Then finally, I asked if I could bring my girlfriend because I will know absolutely nobody at the wedding besides some of my friend's immediate family. She said that she didn't have enough room for her. At that point I said I'd to pass. Was that right? Should I explain to my friend why I won't do it? He seems (quietly) upset about it.For background, I'm not a professional photographer but probably more skilled than your average amateur. Have no experience with weddings.Tldr: friends sister wants me to man a photobooth at her wedding, but can't guarantee I'd have a place to sit, won't pay, and says there's not room to bring my girlfriend (I even said she would eat before she got there). So I told her I couldn't do it. Was I right?Edit: oh and FYI she owns a d3300 with an 18-55 and 70-300. Not ideal but definitely possible to use instead via /r/photography http://ift.tt/2jhHIxd