The upside of the baby registries on Walmart.com or target.com is that people can pick things and just have them mailed directly to you... I agree with Lizbud, it's nice of your MIL to want to have something for you in a tea room, even if it isn't your thing
I just had a diaper shower at the local tea room and it turned out really nice and relaxing There were only 7 of us including me so it was small and personal.