In many old movies, the night scenes were filmed in daylight with filters to make it appear dark, so, I'd imagine that filters that make the grass greener are merely another version of the same technique.
Patrick,
It isn't really the same thing.
If a scene is filmed in daylight with the intention to make it appear night, the whole scene is affected, so one filter suffices.
As Michael states, you can't filter one aspect of colour without it affecting the other colours.
A filter may enhance the green part of the colour spectrum, but it would be at the expense of other parts of the colour spectrum - blues, I think - which would become lighter.
A polarizing filter would remove glare and reflections, enhance the contrast and deepen colours to some degree depending upon the angle of polarization, but I wouldn't imagine it would be consistent throughout the entire telecast.
Perhaps this is what you mean. A polarizing filter isn't really trickery, more of an essential piece of kit for outdoor photography/filming, but it is only going to work if there is light to be polarized, i.e. it won't work as effectively on overcast days.