So I'm prepping my iPhone 4 with hopes of reselling it on Craigslist this weekend. I want to restore it of course. I went the iPhone method by erasing everything. (General.....Reset.....Erase All Content And Settings.) I did this after I had pulled out my old AT&T SIM card. (I'm now using my iPhone 5.) Problem is that now I I'm prompted to insert a SIM to activate the phone. Can I simply throw my old Micro SIM back into the phone, activate it, and then have it set so they can test out the phone when I meet them in person? I'm a little confused right now. Some clarification would be appreciated.