When I took a tour of Temple Square in Salt Lake City with my family I made an occasional discreet comment in a low voice expressing skepticism (I'm an atheist and the rest of my family is Deist in a vague sort of way), but never when anyone else could hear, and certainly not while we were being escorted by a young tour guide! It would have been rude. The only thing I commented on while touring The Vatican was the architecture & art. I would avoid going to the Creation Museum because of the effort needed to restrain myself from laughing out loud... ;-)
As absurd as the Creation Museum is, a small portion of this group seemed needlessly confrontational.
My brother and I toured the Temple Square in Salt Lake City in 1999. A couple of German female Mormons spotted us and showed us some of the more prominent sites. My only complaint was that they were quite pushy about evangelising us and wanted to get us to fill out forms with home addresses and phone numbers.
Did you notice how Church street and State street ran parallel to each other through Salt Lake city? I commented on that to my brother when we were driving.