Why do I not always receive damage protection after a major attack?

Generally, damage protection (DP) will be awarded when a base is damaged more than 50% in an attack, but there are also certain anti-exploit measures in place that may cause a base not to receive protection regardless of how much damage it receives. Some of the specific reasons might be:

1. Your base didn't accrue enough total damage in the attack to award DP (your base must be at least >50% damaged)
2. You currently are or were recently in the same clan as the player you didn't receive DP from.
3. You appear to be an alt account of the player you didn't receive DP from.
4. You are a Facebook friend with the player you didn't receive DP from.
5. DP may also be withheld based on friending history with attackers, and availability of PVP points

Key Words: Damage, Protection, DP, Attack, Defense