I dont even think that you are technically right. Nowhere in the T&C does it say you cannot load for another and nowhere does it say that you have to load yours with your own cc. So the only thing one gets away with is using someone elses cc without ID.
You're theoretically right, that is the cashiers/cs rep should only care if the credit card with which you're loading money is in your name, they shouldn't care whose name is the Redbird into which you are putting money. Much like a bank doesn't really care to match the acct in which you're depositing money with your name.
In reality, some Target stores--most notably a couple in NYC--have taken it upon them to change the rules or enforce their own restrictions/rules, such as: a couple don't allow credit card loading at all, a couple do allow but only $1K/day and matching the Redbird in your name also. No surprise here; a lot of people do commit fraud or money laundering at big box stores (like Target) and some of those activities look like the MS ones....thousands of dollars in transactions, credit cards and gift cards, etc.
For the rest/most of the stores, you can definitely load Redbirds on other people's names with your credit cards. At the stores that I go to they never once asked for my ID to match it with my credit cards, let alone with the Redbird.