I think in this day and age, there is no reason to be poaching tigers, or any other rare game for that matter. I've discussed this with my friends before, the poachers are generally low status people, trying to feed themselves, and they're selling to the highest bidder they can find. Even if you jail the poachers, more will pop up out of desperation. One day, we'll look back and see all of the greed killing rare animals purposefully, rather than the crappy way we move them out of their territories naturally as humans.