If the enemy is within range, so are you. The only thing more accurate than incoming enemy fire is incoming friendly fire. Things which must be shipped together as a set, aren't. Things that must work together, can't be carried to the field that way. Radios will fail as soon as you need fire support.
Radar tends to fail at night and in bad weather, and especially during both.
Anything you do can get you killed, including nothing. Make it too tough for the enemy to get in, and you won't be able to get out. Tracers work both ways. If you take more than your fair share of objectives, you will get more than your fair share of objectives to take. When both sides are convinced they're about to lose, they're both right.