As a retired Museum Curator, that is sometimes true. But there is also a flip side. We had a visitor write a lengthy letter to our Director, complaining that an M1 type carbine on display in the Korean War Gallery was mislabeled as an M2, and General O.P. Smith's Model 1911 pistol should be an M1911A1, not a 1911 "because it was Korea."
We had a policy then to either call or write whoever left the comment or letter, based on what contact info they provided. I called this individual and explained to him that O.P. Smith was issued that pistol as a young officer, and it was an older Model 1911, not a Model 1911A1. As to the carbine, I explained that it was a selective-fire M2 carbine, as stated in the label, not an M1. His response?
"Oh, I never heard of one of those." We had another write complaining that there was not a single M1 Garand on display. At the time there were no less than seven, and I have no idea how he could have missed them?
Yeah, thanks for writing the Director.
Museums try to get it right. Many times, they don't. Sometimes they just don't know, sometimes they don't care, or they don't have sufficient funding to correct a descriptive label or text panel that may or may not be accurate. I have also encountered a few curators that considered themselves above such things, are full of themselves, or are in positions outside of their skill set or expertise. Me personally, would have never asked a visitor to leave, or be removed because they pointed out an error.