Quick question about selling the phone

[SephirothXR]

I just reset my 3G via the "Erase all content and settings" and now I have a screen asking for a sim card and an iTunes icon. I know this is normal, but when I sold my other 3G, all I did was manually delete all accounts/phone data and then sold it to my customer, so all he had to do was put his sim in the phone and it immediately started working on the home screen. This time, if he asks about it, do I just tell him that he puts his SIM in and activates it via iTunes at home and it won't bill him or anything? Will the phone activate like it's nothing? He's buying the phone for a family member, so he has to have his family member's sim card in there when he installs it right?