Restless legs syndrome and soap

I saw this article titled "Can a bar of soap cure your nighttime leg cramps?" and wanted to comment. I think the author is confusing two separate disorders - restless legs syndrome and nocturnal leg cramps. They say that a bar of soap under the mattress may improve restless legs syndrome, but the title implies nocturnal leg cramps. The confusing part is that both conditions may respond to magnesium, which purportedly is given off by soap - I don't know if that is true. But it seems that if magnesium was given off by soap, how would putting it under your mattress help? Also, they mentioned lavender soap may help, as the lavender can help sleep. Maybe, but why not just use lavender aromatherapy? If you have leg cramps or restless legs, see your doctor first.