I probably wrote that article you read about the pygmy sensitivity. I may have overstated the sensitivity since other growers have reported gemmae formation even with light after dark. Other's also confirm that their plants don't make gemmae, and these have been growers using a long day cycle constantly.
I doubt that short term alteration will have any effect (other than possibly with the pygmys, and possibly the winter growing species from the other hemisphere if you are trying to grow them out of their natural season).
The mechanism of flowering in plants is a fascinating process involving a light sensitive molecule. This molecule has a sort of raised arm (based on its structure). This arm is like a key that fits a biological lock. When it is in place, the "circut" is open, and a flowering/growth hormone is produced by the plant. In the dark, this raised arm position degrades, new bonds form and the key no longer fits the lock, so the flowering/growth process is inhibited. This is how short day plants "know" when to flower. The molecule is light sensitive, and if light is provided after dark, the molecule does not degrade, and the key still fits the lock. It takes time to reset that arm, so if a burst of light is given after dark, it raises the arm again, and the short day flowering fprocess is inhibited. This is why X,as cactus must be given no light after dark from about September if you want flowers on Xmas. Bursts of light after dark will reset the clock, so the cactus might not bloom on schedule although it will eventually.
Other processes are also controlled by light/dark cycles: respiration has been mentioned and this is correct. As things go, this seems to be not a critical issue: small mistakes in leaving the lights on will cause little change or harm. Still, plants respond best when conditions are closest to habitat, so I think the optimal plan is to use a timed cycle.
If you are going to be gone for e.g. 3 days, it's better to leave the lights on rather than off. The latter will do little harm, but leaving the plants in the dark will set them back.
I would like to hear more reports regarding the pygmy Drosera sensitivity. Do your plants form gemmae if you give them light after dark?