Yes, you can "steal" a few of them and use them, but don't take them all, as they are the
solar panels that the plant uses to convert sunshine to sugars. If you pick them all and just leave the head of cabbage sitting there like a bowling ball, there isn't anything to photosynthisize with. If you take too many, you'll retard the growth of the cabbage itself.
"The rule of no realm is mine. But all worthy things that are in peril as the world now stands, these are my care. And for my part, I shall not wholly fail in my task if anything that passes through this night can still grow fairer or bear fruit and flower again in days to come. For I too am a steward. Did you not know?" Gandolf
