Try making a big purchase with cash (and not looking Hispanic). Cops get called. Happened to guy I used to work with when he tried to pay cash on a house (not a check, cash).
That's being foolish. Who buys a house with cash, even if you have that much available? I'm sure you can come up with some rare and/or extreme situations where using cash is a problem but 99% of the time, it isn't, at least not in my experience. On the rare occasion that I employ it, I use my debit card as a credit card (no PIN # needed) and for situations where using cash is not feasible, such as making a hotel reservation, car rental, a large purchase (that would be over $200., in my world) or, obviously, an internet purchase (rare, for me) I use the debit-as-credit card or one of my other Visa/MC credit cards. My point is that one can avoid a lot of the bank hassles by simply using cash, something most businesses are happy to receive. As you've pointed out, there are exceptions (aren't there always?) but, again, in my experience, when buying something, from a cup of coffee to a weeks worth of groceries, cash is welcomed as payment.