Barbs ignore ZOC?

I thought for sure I'd seen barbs be affected by Zone of Control before but I just saw a barbarian archer move right past my stationed warrior, getting a second movement. He seemed unaffected by ZOC. This sucked because I'd counted on ZOC in unit placement and he captured a worker AND pillaged a trade route, spawning another barb.

Does anyone know about barbs and ZOC or is this just a random error that I saw? I'm pretty sure I've seen barb ships also ignore ZOC when they were intent on pillaging a trade ship I was protecting, moving around my boat in a loop to get to the trade ship. The common theme seems to be they ignore it when they are going after a trade route, but I'm at a loss why the target would make a difference. Any ideas?

Are you sure you're understanding ZOC correctly?

This is a good, if old article on ZOC.

nevermind, what he did was valid. thanks sillyman.