Yes, there was a time when Ankrahmun had no protection zones on pyramids. Ankrahmun was created in August 2004, however, in August 2005 a year later they added protection zones because of bad apples as noted in Solutions Against Cheaters news article. Yes, it did have to do with the player killing that was going on.
August 11th, 2004 "Major Game Update 7.3"
Ankrahmun first was implemented into Tibia!
July 28th, 2005 "Solutions Against Cheaters"
"...Have you ever been caught in a trap? Now, non-offensive runes will automatically affect the person who uses the rune if there is more than one character standing in this field. Additionally, all ships and the pyramids of Ankrahmun will become protection zones. Also, rope spots cannot be blocked anymore. So you can be sure you will be always able to rope to safety even if there are items lying on the rope spot..."
August 9th, 2005 "Major Game Update: Tibia 7.5"
When the protection zone on Pyramids went into effect.