I've been fighting immigration on this for 25 years. The immigration/customs form requests a US address. As a US citizen, I am not required to have an address and have left it blank for the last 25 years. The last time I was punished in MEM and sent to customs. Customs started to have a go at me and treat me in a very disrespectful manner, like calling me a liar and accusing me of being evasive. When he checked my luggage and found my story to be true, he said sorry and that was that.

In the case of the OP, I would suggest using this little ploy: Begin noting down the name of the person in question who insists on the information. Then state that you are noting down their name so that you can inform the US officials the name of the person who forced you to make a false declaration on a federal document. That is what has gotten me through this mess for the last 25 years If they really really want something, tell them to put "transit to XX999 for XYZ".