For background, see our tutorial on cameras in elevators.
One common criticism of video surveillance is the displacement effect. Improve surveillance and security in one location and this may/can/will shift into another area with less counter measures.
The NY Times has an article discussing a rise in crimes inside elevators, noting that, "elevators have remained particularly crime-prone even as the urban streetscape has become safer."
The article concludes with an observation about surveillance cameras:
"Many elevators now have surveillance cameras, but pointed out that suspects could easily use a hoodie or ball cap as a shield. Indeed, in those three recent crimes in Housing Authority elevators, all since late July, suspects were all wearing caps or hats."
Ceiling mounted cameras in narrow areas make this a particular problem.