I did too. I went to a Titanic exhibit in Boston several years ago. They had a side panel of the ship on display that they had retrieved from the ocean floor. It was in an outside tented area. Still had water being washed over it for preservation purposes. It clearly had a sign on it not to touch it. A guy next to me said: "Oh go ahead, touch it. You know you want to." So I did. Didn't get caught thankfully.
Same here, in Boston.
I mentioned this a few years ago here and was berated by a fellow freeper for doing it.