It's not "gun dumb". It's personal preference. If it's not something you want, don't buy the model with it. I applaud S&W for giving the firearms enthusiast a choice.

My M&P 9 doesn't have a frame safety. I'm a Glock owner so it's no big deal to me not having a safety. Keep your finger off the trigger until you are ready to shoot: aware of the foreground, the target, and the background.

My 1911 has a frame safety that I find easy to use, and not intrusive. A reflexive flick of the thumb, and the safety is off. I have a M&P 22 that has a frame safety, and I find it as easy to use and unobtrusive as a 1911's safety.

I agree with Jeb21. John Moses Browning got it right with the thumb safety concept. I don't like those little, hard to activate/deactivate, nub safeties that sit basically flush to the weapon. I also don't like the slide mounted safety system a-la Beretta 90-series.

***EDIT***

The Shield is an odd one. The one I fondled at the LGS had a pretty stout safety. It wasn't easy to engage/disengage it by accident. It took a bit of pressure. I'm not a big fan that style safety. At least S&W made it as unobtrusive as possible. If you don't want to use it, leave it disengaged.

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-John