[ForHackernews]

> just enter bank issued debit card for fee-free transactions.

IIRC, Square is only able to do this by abusing the "refund" feature of debit cards to credit money to those accounts. I read an article a while back that claimed the banks were not happy about this, and considering shutting it down (or rate-limiting it) in the future.

[Vraxx]

I believe that was only speculation as to the method.. Though the alternative that was speculated was transfers at a loss to Square (with an increased user base as the motive).