For hiking in polar bear country, this answer cites a page that advices to avoid camping under the stars at all times. Yet people do go trekking on Svalbard, and I don't think the density of huts is such that people stay can avoid camping. For example, this company offers a multi-day trek including a night in an expedition tent.
How can those two statements fit together? Does this company take risks? Do they know areas where polar bears don't go? Or is the expedition tent somehow polar-bear proof (sounds unlikely)? In summary, how do people safely engage in multi-day treks in polar bear country?