An encounter with severe turbulence and rotors on take off or approach / landing is a dangerous event in my book.
Prob 30 tempo; a 30% chance that it will be there 50% of the time. Not far off the odds you get playing Russian roulette. As for the actual, you won't know it's there or how bad it is until you're in it.
Better to arrive late than dead in my book, I'd say sensible rather than risk averse........