I read a post by a fellow FTer about the language at the top of the FINCEN form saying "when purchasing more than $3000 with CASH". And how he/she pointed it out to the manager and they agreed with him/her.
Well, I had success in buying more than $3k at a Walmart I frequent. The cashier actually told me it was okay because I was paying by debit. I was floored. You win some, you lose some.