Although equipment manufacturers refer to this acronym as Non-Line-of-Site, experienced designers and installers know this as Near-Line-of-Site. Those wireless technologies that incorporate the modulation scheme that allows Fresnel Zone encroachment while still maintaining a link (OFDM), albeit at lower data rates, must be carefully considered.
Because obstructions vary in their makeup and attenuation properties e.g. leaves, brick, steel, wood, glass, etc., pre-calculating a link budget with line of site obstruction is next to impossible without a link validation and bandwidth test. In general, since most of these technologies are unlicensed, they should be engineered for complete line of site thus allowing headroom and fade margin for any potential frequency interference or environmental issues that may arise in the future.
In short, always try to engineer an outdoor wireless network with proper line of site. If you are planning an NLOS connection, try it first and make certain the bandwidth results meet your application requirements. If you treat an unlicensed network design like a licensed microwave design, you will improve the performance of your unlicensed deployments by tenfold.