That orthopedic sandal might be good for prevention. Of course, how do you know you need to prevent it? You never know until it's too late. Plantar Faciitis is basically tendonitis (tight tendon) in the bottom of your foot. The cure is to stretch and loosen it back the way it's supposed to be. In theory, the Strassburg sock gently stretches the tendon while you sleep. Any stretching will help, as long as you don't make things even worse through inflammation. What the rolling-your-foot-on-a-frozen-bottle accomplishes is to stretch the tendons without causing a lot of swelling due to inflammation.
The pain of Plantar Faciitis tends to go away as you use your foot and the tendons warm up. So I suppose gently stretching your arch after warming up might help - the keyword being "gentle."