This question arises in my office every day. While I do refer patients to plastic surgeons for tummy tucks occasionally, the majority of patients can be treated with a combination of tumescent liposuction and smart lipo. Notice that I said, tumescent liposuction and smart lipo, not just smart lipo.
What this all comes down to is picking your surgeon wisely. If you go to a dermatologist for your liposuction, there is a good chance that you won't need the tummy tuck, but if you go to a plastic surgeon for it, you probably will get one whether you need it or not. On the other hand, if you go to a 'cosmetic surgeon' du jour (family practice, ObGyn, or 'other'), goodness only knows what you will get, but it won't be good.
The key factor here is making sure that the doctor does excellent tumescent liposuction, because the other part of it, the smart lipo, is only the icing on the cake, while the initial part is where it all will either be made or not. So, choose wisely and hopefully you can get away without having the pain, cost, long recovery time and risk of the tummy tuck as well as the 12 inch scar. Good luck!