Looks like 4th time is the charm. Called MR and asked about bonus code 5721 for the Business Platinum. Got a very nice rep who offered to set up all the cards for us himself (he said he'd just changed departments and just learned how to add cards and he actually seemed excited about doing it!). My dad added 5 gold cards (free the first year, $35/yr after that) and even my 14 year old brother -- seems like there is no age limit. We were not asked for SSN.