Thank you for the deodorant soap suggestion. Actually this is for my cat hating neighbor. She isn't really cat hating, more afraid of cats then anything else. She doesn't mind them on the lawn, but she is too afraid to sit out on her patio if she sees a cat around.
I've been very successful with keeping my own cats from digging up my flower beds. I used the spray bottle method. What I do, is watch over the flower beds by the house in the spring. And if the little darlings start digging, I spray them with warm water. I've used this method in the house too, away from the good furniture of course. Over time the cats associate the spray of water (which most cats hate) and he flower beds, the cats don't dig in them nearly so much. Even if I just pick up the bottle and say "spray bottle" they will think twice about what they were about to do.
However, just lining up spray bottles in the garden wouldn't do much good, I would think. There has to be a person on the other end of the bottle.