Quoted from GregCon:

It's getting to where it won't be possible to buy or sell anything before long......let's not forget, for all the cash-on-glass crowd, that if a drug dealer were to sell a lot of marijuana pills and receive in return a wad of counterfeit $100 bills...he might be the guy buying your machine. This is where the term 'funny money' comes from.
I'd have no problem with a personal check; if I had spoken with the buyer on the phone and he sounded OK. Additionally, if the check arrived from the Bank of Nigeria and the buyer's name was Hugh J. McLovin' I'd be far more concerned than if it arrived from a normal bank and the buyer's name was Mr. and Mrs. Leonard Lubinsky and had puppy dogs or flowers on the background.
I find that as Planet Earth accelerates through time there seems to be an entire breed of people developing who are distinguished by their belief that they will go through life first and foremost avoiding all risks at all costs.