Related to this question, roughly how rare are (!!!) bushes? I have the required number of steps and I've encountered around eight (!!) bushes, and spent around 2000W on Poke Radar turns, but haven't seen a single (!!!) bush.
Triple exclamation mark bushes are more common with the number of steps taken. Depending on the course, the minimum steps to get triple exclamation mark bushes vary, with more steps being required with courses that are unlocked later.