During your consultation comment on her dry brittle nails, and if there is any peeling. Explain how water is the main culprit for this....dry brittle nails need oiling not watering therefore you will not be soaking her nails in water during the manicure, but using products that will soften and help remove the cuticle during the service. Also use this time to reinforce she should be wearing rubber gloves when doing dishes to help her dry brittle nails, and using a good cuticle oil, especially if you sell cuticle oil
If she has fabulous strong nails with no weaknesses, dryness or peeling, then use your own judgement on whether to soak, I still wouldn't and say it was a preventative method of manicure to stop dry brittle nails....but that's just me lol