i did not think it made much difference.
firstly, use of lights can be wasteful, but hardly the end of the world when we use them espcially as a growing number use green lightbulbs which are more energy efficient.
secondly, why at 8:30 pm when it is dark? just for photo opportunities? using light at night is hardly "wasting" electricity. we need light to see what we are doing, whether it is for driving, for doing work, for cooking, for reading etc. who are we to say that whatever that person is doing has is not important and has to wait. Why not tell everyone to switch off their lights at midday, as there is enough natural light for most places to be wasting electricity if they are turned on.
thirdly, everyone is looking out for themselves. there is no incentive to change their ways and go green unless it benefits them. Electric cars are not successful yet, as they only go about 60 miles on a full charge, and then there are not enough recharging stations to make it a good purchase for most families. Whereas energy efficient air con, light bulbs, etc. have tangible savings on electricity bills.