Does anyone have any clue what the legal implications are of a store refusing a particular debit card?
Eg, welfare-mart kiosk has not worked with OV GC for months for me at multiple locations. Obviously a block to the particular card. It interests me that bluebird/etc is technically a bank since it is owned by AMEX. They are forced to follow some pretty strict rules that stores are not. It is obvious that this is in violation of the merchant agreement, however are there any potential legal implications for wmt/bluebird for refusal of a particular card that has the word debit on it?

No, don't go mad at welfare-mart and call your congressman, it will only make things worse.