Great idea - thanks! I will plan on contacting them tomorrow if I don't receive the badges/email today. Especially with the 4th of July weekend being in the mix - it's probably better to get in touch with them before that rather than after!
Very true on the "before" part, but they will have significant staff devoted to such issues right now.
Stuff can happen to emails. So you should also log in to SDCC MemberID - There's a tab for "badge shipping". Right below the opening paragrah about address changes etc., a "Shipping Information" section appears when the email is generated, with a link to the USPS tracking page. Remember that "it's shipped" starts when they generate the mailing label, and it can take a couple of days for the package actually to leave the Detroit depot. My package made it to the local P.O. at 6:45 this Friday morning, so I'll delay leaving for a long drive until I find out if it made it onto the local delivery truck.
There's also a new "Merch" tag where you can order 2017 shirts-hats-bags for pickup at the Con.