Teams picked up a packet with a 11x17 sized obverse of the 1998 series 20 dollar bill, and then they pull out the magnifying glass
The border appears to have a pattern and when compared to a $20 from their wallet reveals other missing items.
The serial number has extra letters/numbers, and there are missing letters from words on the bill.
BTW, with regards to copying money see Title 18 U.S.C. 474 & 504. Basically 150% and educational. See Regan v Time U.S. Supreme Court 1984