err on the side of something: o que isso significa?

Imagine you and your friend climbed up a cliff and now you're thinking of jumping off the cliff into the sea that's right beside the cliff. You think for a moment and realize that's a very extreme action and say to your friend: Let's err on the side of caution and only watch the sunset from here.

When you err on the side of something, it means you choose an action that may be too extreme. You thought an adventure like that would be too challenging for you and maybe would put your life at risk, so you decided to err on the side of caution and not jump. That's all. Take care!