Furthermore, T-list sites are not usually major tourist attraction and can be down right "way, way off the beaten path". Thus, one is more likely to visit WHS unless one is actually trying to visit sites on the T-list. I do second the thought that the lack of information on the T-list sites is also an important factor in the difference in visiting number. Finally, some T-list sites (Grand Pre) don't want attention and actively discourage tourists. On the other hand, if your on the WH list, then you probably like tourists.