Comment by scott_s

This may be the same thing as what you call the whitelist, but in case it isn't: on iPhones, you can mark some contacts as "Emergency Bypass On." Even in silent mode, you will always hear calls and texts from them. You can also choose sounds unique to that person. I have the bypass on for my fiancee, and I chose a pleasant, unobtrusive sound for her texts. I have found this works quite well.