[Edi]

Not quite. An across the board lv 2 search will net you roughly 85% of possible random sites. It will miss the common (and commonly found) lv 3 sites for FAWESDN (Bronze Pillar, Cave of Clouds, Weeping Stone, Iron Cliff, Crystal Garden, Well of Pestilence and Grove of Evergreens) that each provide 1 gem of the site type. Well of Pestilence also increases death scale, so it's easy to spot unless you have death dominion. The others need either lv 3 search or radar spell. But generally that income is peanuts compared to the general lv 1 and 2 sites.