Most museums prohibit photography of any type especially flashflash photography; which is the basis of the camera ban.
I don't think you would be denied entryFor example, but you would be askedthe MoMA PS1 has this to be aware ofsay:
Photography is allowed in the museum. Visitors can use small cameras and cellphone cameras. Flash photography, videography, tripods, and photography for professional purposes are not allowed.
Here is the photo policy; as like yourselfjustification from MoMA PS1 Director Klaus Biesenbach for this change (previously, many tourists carry cameras with them so it would be impractical to ban people from entry.were strictly forbidden):
Cameras are ubiquitous in daily life because of cell phones and other devices. More pictures are taken than are on display. Today, taking pictures is a participatory way of visiting exhibitions, and we embrace this creative and proactive viewing practice.
At some locations, you may be asked to store your camera at the coat check or other such station.Source: Hyperallergic
Keep in mind that most of these artworks are kept under strict atmospheric conditions (including the type and intensity of light and the amount of moisture in the air, among others) and photography can easily ruin these priceless works.
Not to mention, a bunch of clacking of the shutter is really distracting. Again, I have to stress the entire no-flash issue.
Although a large majority of the works on display are in the public domain (so there are no copyright issues) but they may be under other restriction for reproduction.