tron if it happens at night/dark I don't see a problem.
(I doubt your mum walks her dog in the dark on her own).
They don't only do it in the dark. They don't only "prey" on people who want the attention and the only reason people can't walk their dogs in the dark alone in parks is because there's some dodgy people about making it unpleasant.
Several of my favourite kite/bike locations are dogging hotspots (goes with the territory, remote car parks I guess) and when there's the odd couple there getting it on it's hardly a problem, but when there's 4 or 5 cars full and an organised operation it's a different matter. It's uncomfortable to have to get changed/packed away next to a car where people are standing round the outside having a shuffle. It's unpleasant to get off the water, get changed in your car only to find some random ugly sod standing at your drivers window watching you get out of a wetsuit, and it's intimidating for my partner who often stays in the car to read while I surf and finds herself being propositioned by people with their bits out around the car.
Don't give me the "dogging is harmless" nonsense.