Polling locations are, by necessity, formed out of locations that do other things the rest of the year. Schools, churches, community centers, and the like. They sometimes have cameras installed.
Because voting is private, there are restrictions on filming in polling places. This applies not only to ballot selfies, but to video surveillance. In addition to potential violations of privacy, the use of surveillance cameras filming voters can also be seen as intimidation. For both these reasons, cameras in a polling location may be covered for the day.
This covering of cameras is distinct from use of cameras in counting locations, which often do have surveillance cameras, some of which are mandated by state laws.
The Conspiracy Theory
This is currently a very small conspiracy theory at the moment, with almost no uptake. But it’s worth explaining it beforehand in case there is uptake later. An example of the Obstruction of Oversight and Destruction of Evidence cluster of theories, the idea is that the cameras are covered so that devious poll-workers can execute Sharpiegate-like deceptions. What makes this potentially compelling as a conspiracy theory is that there is a participatory element to it. A variety of people can take pictures of the cameras with sincerely confused questions about what is going on, and that confusion can be leveraged. But as stated above, the cameras are not meant to be there in the first place. They are there because polling locations are repurposed, and, for example, letting the local church film people voting just because they lent the city a location for the day would be really creepy.
On the whole it’s a good example of the detail-generated conspiracy theories (see Kapferer) that dominate the election space.