While I was about to pack my stuff after visiting the customer, the spot where I parked had a small rectangle "park". Since I had a bit of time, I decided to test the remote's distance myself. So, I set my D50 down on one end of the park and set it to receive the remote's signal. I just wanted to see how far it can go (assuming its using a fresh CR2025) battery. Some said it was about 16 feet (5.3 meters) on the Internet.
As I walked towards the end, I activated the remote at roughly every five meters.
Distance: 5 meters.
God, my backside is huge! Yes, I prefer loose jeans, OK?
And my back looked weird
Distance: 15 meters
Distance: 20 meters
Distance: 25 meters or so
So, the remote is quite effective up to about less than 25 meters. But maybe, the distance could be more in an enclosed area since there will be no interference from the Sun (which is not only bright but a source of infra-red as well). Anyway, for it to be effective, the remote must be used straight since at any other angles, it will be blocked either by the lens or the handgrip. Moreover, I have yet to try reflecting the remote's infra-red signals back from a distance of more than five metres.