Is it safe to give someone your TiVo Service Number?

I am currently selling a Premiere with lifetime service on ebay. Someone asked me to give him my TiVo Service Number so that he can confirm my unit's lifetime service is still active. Is this okay to do? On my listing I included a pic of my screen that clearly says the lifetime is valid. I blacked out my TSN. Is this a scam? What can he do with my account if he has my TSN?