I'm constantly reminding fixed wing and light heli traffic of the risk of rotor wash when FISOing, alsthough we can't delay traffic for it - we have a based MD902 who occasionally departs/ lands along the active runway and even the odd Puma and Merlin- we warn the departing or landing traffic 'caution rotor wash' - most take the hint and wait a minute or so, although a few don't - have seen a couple of Cessnas nearly come a croppa !