Perfidy, or the practice of deceiving the enemy by lulling them into false confidence and then attacking, should be stopped. Although many wartime tactics are suspect, perfidy deliberately abuses the unspoken agreements of what is "acceptable" behavior in a military exchange. Considering perfidy a war crime shows that no one accepts tactics that involve "fighting dirty."
Sometimes it is necessary for an army to do almost anything they can in order to capture or kill an enemy target. I think using trickery is one of the least negative things someone could do to capture or kill someone. If we call it a war crime every time someone does this, there would be too many people or armies going against this war crime.
It should not be considered a war crime to use trickery to capture an enemy combatant, that's called good strategy. When you are dealing with killers and bombers and people who behead others there are no rules. We will get you with any means necessary. There are no rules of engagement that will save you from our wrath. Period.
No, it should not be considered a war crime to use trickery in order to capture or kill an enemy. When people are in war, there are still certain rules, but capturing or killing the enemy is not one of them. It doesn't matter how they do it. If someone used trickery in war, that just means they are a good strategist, which should be encouraged.