A very apt question by icemelt. Global warming really affects the forum now. I, personally, believe, however unscientific it sounds, that nothing in the world is absolute; except the statement itself. Take light's speed (versus Tachyons, particles supposedly having higher velocity than light, defying the theory of relativity) or absolute temperature (maybe in some day scientists will go below 0 degree Kelvin). This is only expected, as absolute or relative, is relative to the basis of the present knowledge.
Regarding the 'trapping' of light in this instance, it happens to me that this property could be used in 'compacting' of information; much like 'zipping' as in Win-Zip. The strange behavior of light will take time to be explained, by using 'quantum theory', perhaps.