Yes, this screen grounding business really exercises a lot of self professed ex spurts. As with most things in life, there is no absolute right or wrong method. There are some cases where grounding one end is best and other where both ends is best. You keep both as options in your toolbox when you tackle EMC issues.

Where a lot of these people get ahead of themselves is by forgetting that there is no hard "ground" from an EMC point of view. When you have to test and certify an installation, the limits apply all the way up to 30MHz, at which point the distances on a large system start to approach the wavelength of the measurement frequency. The screens may now start to form a part of the resonant network that is causing some of the problem. I speak as someone who has had to get reasonably high power (100kW) motor / dyno installations systems to meet the EMC limits.