...the "jump, if..." condition, to be precise. If the condition depends exclusively on a random variable the jump (or a spawn condition) will be executed prior to the planning phase, so all units are at one of their starting locations. That way you can also randomize the starting location of the player's units, or, with the Spawn function, randomize the composition of the player's units.
This is being demonstrated in one of SB Pro's stock scenarios, Desert Ambush if I remember it correctly, which has a total of more than 50 ways how it can play out - one of three different types of enemy taking one of three different routes, with the player being equipped with one of six or so different types of task forces - 3 x 3 x 6 = 54 variations.