Some of the bills I have seen passed are pretty pitiful, even printed on computer paper.
The suspects I have caught purposely went to busy convenience stores during a busy time of day to ensure the cashier was in a hurry and distracted.
Since most businesses use a marker to check bill $20 and above I am seeing a lot more small bills counterfeited. I am also seeing a lot more $5 bills washed and printed over with larger bills so they still mark as a valid bill.
It doesn't surprise me at all that some of the bills passed, I'd be willing to bet a lot of clerks couldn't tell you who is supposed to be on a $100 bill if you caught them off guard.
For some reason the Walmart gas station in my jurisdiction is where we get 95% of of our forged currency complaints. Dont know if thats because people choose it to pass bills for some reason, or becuase they are doing more to check for phony bills.