I went to an Ansel Adams exhibit in Kawasaki City one time in the mid '90s. My mother and I were 66% of the patrons that morning, which was a pretty unusual situation for a Japanese museum.
Anyway, we had plenty of time, so I walked right up to a lot of the prints and looked at them from almost nose length. An elderly museum staff member came up and asked me and asked if I was a photographer.
He actually encouraged me to keep doing that. Wanted to make sure I got to absorb every possible detail, as he had done.
Come to think of it, I went to a Picasso exhibit somewhere else in Tokyo right around the same time. There were no barriers or ropes to keep one away from the displays, so lots of folks were getting very close. No touching of course.