The practice of locating natural gas and petroleum deposits has been transformed dramatically in the last 20 years with the advent of extremely advanced, ingenious technology. In the early days of the industry, the only way of locating underground petroleum and natural gas deposits was to search for surface evidence of these underground formations.
Thumb Safety. No, the problem with a Thumb Safety is it's a Minor Motor Skill the way your brain see's it. Under a stressful situation you may loose all minor motor skills. All my guns I train with and I train consistantly, do not have any safeties.
No way on the M&P. A proper thumb/frame safety like on a M1911 is shaped so you can keep your thumb on top of it at all times, safed or not. The M&P design doesn't lend itself to this.