When your going somewhere like McDonalds or any other prime bum gathering ground and you only bring a credit/ debit card instead of cash. This leads to a very simple "no i don't have any money on me" or "i only brought plastic" response when pestered for change by bums. Its a quick simple way to relieve yourself of the guilt incurred by making other dumb excuses as to why you won't give a bum money.
Guy 1: Man i just got guilt tripped into giving this bum all my spare change outside of McDonalds
Guy 2: I'm telling you, just use the anti-bum card and you won't feel guilty about refusing them money
Underage Guy 3: I got a bum to get me a 30 pack last night
Guy 2: I knew there was a reason god made bums