No offense meant, but some answers:
A) There is a
sear disconnect lever inside the pistol that you hit to eliminate the need to pull the trigger. Did you not read your owner manual... or is your's somehow different? The fact pressing the trigger to field strip the M&P is unneeded is actually one of the "features" of the pistol, which differentiates it from most pistols on the market.
B) Removing the "tool" in the grip panel is the device you use to manipulate the sear disconnect lever inside the pistol (again, did you not read your owner manual?

)
C) The warning is there for the lawyers since some of the M&Ps have a magazine disconnect feature (for places like CA)... the ones w/o the magazine disconnect have the stamped lawyer-speak.
Hope that clarifies a few things and removes some incorrect info. If somehow there are models that do not have the sear disconnect lever, please let me know. AFAIK, they
all have this "feature."