I think the confusing part here is the word "induce." The word implies that there's some action you can perform to artificially force a plant to produce a spike.
To my knowledge, there is no way under normal culture to "force" a Phalaenopsis to spike before it's ready to do so on its own. In a laboratory environment, there may very well be certain hormones that can be applied which will actually induce spiking artificially, outside of the normal time frame, but other than that, no.
Spikes are triggered by a plant's genetics responding to environmental conditions. On some Phals, both the onset of warmth and higher light levels in spring are needed to trigger spiking. On other Phals, the fall or winter bloomers, both cooler temperatures and lower light levels are needed--completely the opposite.
The statement "cooler temperatures will induce a Phal to spike" is erroneous. It's just not true. Cooler temperatures may be needed to trigger some Phals to spike, but only the ones whose genetics are programmed to respond to that kind of change as an actual trigger. It'll have absolutely zero effect on the others.
The drastic reduction of light, however, creates an environment that tricks plants into "thinking" it's not a good time to flower yet. It won't "induce" spikes, but it will delay them until some further time down the road when normal light levels are restored.
I have not heard of any growers using a drastic temperature drop alone for several months to achieve the same effect. I imagine that such a thing might work to delay spiking, but I also imagine that creating such conditions would be a lot more difficult and expensive than just putting up a tarp.
Hope that helps some.