Airsoft is all about being able to make decisions in the field, on the fly, based on the circumstances of the engagement.
Where we play, we have no MED distance within reason, (No shooting at someone from like, 20 feet.) so people DO fear getting hit, as it'll occasionally draw blood... and after you've killed someone with superior tactics and firepower multiple times, they DO fear you. Because they've been psychologically beaten already.
If you're crossing an open field to a heavy tree line, you might want to rethink just what you're doing.
If you can't SEE where your opponents can hide, you shouldn't be running into the situation.
Now, my personal philosophy is to aggressively take ground, and outflank opponents. When this isn't possible, I think it's then best to use superior range and accuracy to keep them at LEAST pinned down, or possibly take them out.
But, my tactics are based around a highly mobile squad of 4 in light gear with upgraded weapons.
Your tactics need to suit what you're using.