The very sudden no-warning drop in pedaling resistance can cause you to lose control of the bike and/or fall off. The (old) SA 3-speed's drop into neutral and the (current) SA 8-speed's drop into first, though they may differ in their etiology, do present the rider with much the same risk of potentially very serious bodily injury or worse.

See, for example, http://www.bikeforums.net/showthread.php?p=7979202#54

Regards
T

P.S. Again, there is reportedly a new version of the SA 8-speed hub in which this problem (innocuously called "adjustment sensitivity" on the Sunrace/Sturmey-Archer blog) is said to have been eliminated. SA has said that the new version will be released after U.S. distributors have sold their stocks of the old version: "Once any remaining 8 speed hubs that are in the US are sold, our distributors will be supplied with the new version."