Golden_Gaze list the warrior code and cats who have broken each rule.
Rule 1 was broken by Graystripe when he was torn between his loyalties to Thunderclan and Riverclan due to his love relationship with Silverstream, and refused to fight her. This rule was also broken by Bleufur when she fell in love with Oakheart, and refused to battle him when he was attacked by thistleclaw. It was also broken by any cat who joined the Dark Forest. This was broken by Fallenstar and Readfeather when they gave birth to Graypool and Willowbreeze.
Rule 2 is one of the most frequently broken, with many Clans crossing boundaries to catch prey or apprentices not acknowledging the boundaries.
Rule 3 was broken by Firepaw when catching prey for Yellowfang after she was exiled from Shadowclan. It was also broken by Longtail and Darkstripe, who ate prey on a hunting patrol instead of bringing it back to the elders and kits. It is rumored by Graypaw that Sandpaw and dustpaw did this every so often.
Rule 4 was broken by Tigerstar and his warriors when he killed prey only to raise a hill of bones.
Rule 5 was broken by Brokenstar of ShadowClan, when he forced kits to become apprentices before they were old enough. He also trained them too hard, killing some of them. Some were made warriors before they were even six moons old. This rule was also broken when Bluestar apprenticed Cinderpaw and Brakenpaw before they were six moons old.
Rule 6 was broken when Squirrelflight was named a warrior, but did not sit vigil, as ThunderClan did not yet have a camp. This comes into conflict with her story in code of the clans, where she gives vigil tips and shares experiences from her own vigil.
Rule 7 was broken by Firestar when he appointed Brambleclaw as deputy because he had no apprentice, even though he was going to mentor Berrykit when he became six moons. This rule was also broken when Hawkfrost was appointed temporarily as deputy, since he hadn’t mentored an apprentice.
Rule 8 was broken by Tallstar when he appointed Onewhisker leader, even though Mudclaw was still deputy.
Rule 9 was broken by Bluestar when she waited for too long to name a new deputy, and when Firestar refused to name a deputy when Graystripe disappeared.
Rule 10 was broken by all Clans when they fought numerous times at Gatherings.
Rule 11 was broken by Shadowclan when they stopped believing in StarClan and stopped patrolling their borders.
Rule 12 was broken by Russetfur and her patrol, watching Berrykit struggle with his tail caught in a fox trap, and making no move to help him. Also done by Tigerstar when he was an apprentice and tried to kill Scourge while he was a kit named Tiny.
Rule 13 was broken by Fireheart when he refused to attack WindClan when Bluestar planned an attack.
Rule 14 was broken by Brokenstar, Hawkheart, Tigerstar, Hollyleaf, Lionblaze, and Clawface when they killed cats to win their own battles.
Rule 15 was broken by Cloudpaw when he took food from Twolegs and by Skyclans’s daylight warriors because they live with Twolegs at night. Also by Pinestar when he left Clan life to be a kittypet.