BSM allows the best of both worlds and is an additional tool, it is absolutely NO replacement for using mirrors or checking your shoulder!!!!!
While I am VERY happy to hear the good feedback about the BSM, I must continuously remind people that this is an assistance tool. While it is incredibly helpful, one must be careful not to rely on it, entirely.
I see BSM roll-out the same as I watched ABS come out on cars. While ABS had some shortfalls in the intruduction phases, it could easily be misused and falsely relied upon. Today, with Dynamic Stability control, the systems are super reliable and in many cases make cars more fun to drive. BSM will follow the same rules... So, enjoy the BSM, but do NOT forget to check your shoulder!!! Drive responsible.
In the future, maybe BSM would even prevent you from changing the lane altogether? The future of BSM is really limitless!!!