I used to work for Philips' TV branch, they used a similar setup. Instead of a camera they mounted a light sensor to the display and measured end-to-end delay for various color transitions (white-to-black, black-to-white, ...). All other manufacturers and many serious reviewers perform similar tests.
Of course, these tests are always performed with all built-in image processing disabled, those can easily add 2 frames of delay on modern televisions. MPEG deblocking and noise removal are performed by most TV brands to improve image quality at a cost of latency.
Of course, these tests are always performed with all built-in image processing disabled, those can easily add 2 frames of delay on modern televisions. MPEG deblocking and noise removal are performed by most TV brands to improve image quality at a cost of latency.