Ski trip

Megan
Okay, so my in laws signed us up for this ski trip in February, and at the time I'll be about 10 weeks along. Obviously, I'm not going to want to go downhill skiing. Also they are big hot tub/drinkers. We don't want to announce the pregnancy until after we get through the first trimester, and I don't think we can even trust them to keep a secret because they're big blabber mouths. How do I avoid these things and still be polite, and not give myself away? They already don't think super highly of me, and I want to avoid sounding like a snob if possible, but of course baby comes first.