There's a difference. Always honour a threat. The weight of all of your equipment is proportional to the cube of the time you have been carrying it. Hell hath no fury like a non-combatant. A lost battle is a battle one thinks one has lost.
Surprise is an event that takes place in the mind of a commander.
All warfare is based on deception. A little caution outflanks a large cavalry. No combat ready squad ever passed inspection. No inspection ready squad ever passed combat. Five second grenade fuses burn down in three seconds.