About high velocities:
http://mackila.com/airsoft/atp/ - study this

Very cool shot 112 meters
0.36 BB. Energy of rifle 200 m/s 0.2
Co2 SVD kit can fire about 300 m/s... But 250 is HARD limit. My sniper rifle is AEG and has (calculate to 0.2 BB) 193 m/s. 85-90 meters are 20-30% hits. But wing is serious obstacle.

About pyros - we are trying to play far form others living. Forest, abandoned military base etc.
And sound tripwires are not killing by defaults. But you are right, in buildings a lot of grenades can make you feel not good.