What is one important guideline when employing artificial obstacles?

One important guideline when employing artificial obstacles is to locate them beyond hand grenade range of your position. This is crucial for maintaining the safety and effectiveness of your defensive positioning. By ensuring that the obstacles are placed at a distance greater than the range of hand grenades, you minimize the risk of the enemy using grenades to neutralize or bypass your obstacles. This strategy helps to maintain the integrity of your defense, allowing for better control of the battlefield and reducing the potential for enemy infiltration or attacks that could compromise your position.

The other choices can lead to vulnerabilities. For example, placing obstacles within visual range of the enemy could allow them to easily target and neutralize these barriers, while blocking all visibility can hinder your own forces' ability to monitor the battlefield effectively. Constructing obstacles in open areas may also make them more susceptible to enemy attack, as they can be easily seen and targeted. Thus, situating obstacles beyond hand grenade range is a sound tactical decision that upholds defensive principles and enhances overall operational security.