I agree Poachers will always be a problem whilst the Demand for Tiger fur and parts is still around
On the plus side though the article does say about them connecting up conservation areas with this new location and the High Altitude will mean you need some serious kit or already be acclimatised. A tigers range is also huge, so that will help a little. With any luck these two Tigers that they witnessed know better than to go near any Humans.
I'm sure though that folks will be doing something to protect them now that they know they are there... I would hope so anyway.