Yes, unfortunately scarring is the price to be paid when you undergo surgery. In the case of a tummy tuck, similar to when a tailor removes extra fabric, a surgeon removes extra skin and scars are just a part of the tradeoff one needs to accept.
A meticulous surgeon will do everything he can do to minimize the visibility of the scars. Some scars tend to be more noticeable than others, and this can depend on several factors. Skin tone and elasticity, genetics, and skin quality as well as the actual length of the incision will all play a role in how visible the scar is.
Generally though, given at least a year a scar will heal nicely and lighten up considerably, which will decrease its visibility exponentially. And because of its location along the bikini line, it really isn’t something one notices unless looking for it. Most patients are so happy with improved abdominal contouring post-op that the scarring is just a minor nuisance.