Yep! Crazy right? My sister-in-law is a huge anti-ultrasound advocate, I'll see if I can find you some of the links she pulls out of no where.
I imagine she thinks it causes harm in the same way x-ray does (although I'm just guessing obviously). I don't think it's strange at all that less-educated people would be scared of it, since it all 'kinda looks alike' if you're not well informed. See-through technology with waves and whatnot