This was not allowed in 2009 (no frozen chai, no frozen coffee drinks either...all were cash only)
Here's the link to allowed snacks in 2010 (as reported from Disers who have successfully used snack credits at these places this year) Looks like frozen lemonade is about it for frozen drinks at Anandapur Carts...and they may be talking about the prepackaged Min. Maid cups that have been around AK for several years.