I've been out of the Credit Card rewards game for about a month, and much has changed in that small time frame.
So I got my Wells Fargo Propel card in the mail (40,000 points for spending $3000 in the first 3 months) and proceeded to buy a $500 Vanilla Visa Card from my local drugstore. I went to Walmart and could not transfer it using their Moneycenter machines. I went to the clerk and asked for a Bluebird reload and same thing.. the clerk said it can only be used as a Credit Card (which is not a valid way to load Bluebird cards.) Thinking it was a glitch at my local Walmart, I tried another location a few miles away. Same thing.
Since I haven't been following news regarding credit card rewards, I decided to check on MillionMileSecrets and found that Walmart has disabled Vanilla Visa cards from reloading Bluebird. So I was left with a $500 prepaid debit card to spend down. Oh well, my total loss from this experience was just the $4.95 activation fee and 2 hours of my afternoon.
It seems, as of 6/23/2014, prepaid VISA cards issued by US Bank and Metabank are still accepted at Walmart Moneycenters for reloading Bluebirds. (In an earlier post, I talked about earning 2.5% effective rewards after fees by buying gift cards at Staples with the Chase Business Cards.. I think those are issued by Metabank.)
Later, after reading the blog post, I went to Ralphs and purchased one of their $500 gift cards issued by US Bank (I double-checked the back and was absolutely sure before making the purchase.) I was able to load my Bluebird with that card at Walmart without any issues. Note that a pin is preassigned to these gift cards and the fee is $5.95 instead of $4.95 for Vanilla Visas. Also if you don't have Ralphs in your area, try a Krogers.