The entire group heard the threat. Stealing from her or her children was an absolute. Stealing anything was against the rules. This was clearly directed at the fact that the ice dragon could tell that they were all in awe of the materials in the garden. Let alone the entire castle. This castle was her hoard. The jewel that showed off what she had when it came to power.
"So tell me, children. What do you have to do with me? I have never had anyone come to me like you have. Those other humans all came with worry and fear. They needed me and what I had. What do you need." The ice dragon was not a fool. She knew that they had come for reasons.