Grey waste disposal

Stayed at a CL a few years ago and asked about waste water disposal.  The owner said to sling it over the back in the hedge.  I just wonder if we are being too fussy with all our fancy waste disposal containers?  I know it depends what is in the waste, but if it has just been used for hand washing or shower I should think there wouldn't be a problem.  Many people use waste water on their gardens.

Perhaps this is more of a problem on Club sites (which we rarely use) where the vans are close together and the vans are pitched in the same spot every time.