Tracing Cash

[Eric Blossom]

> BTW, cash can be traced even without bar codes, since serial numbers can
> be read by OCR.  

The few $50 and $100 bills I've looked at over the past year or so
have had a light colored vertical stripe on them that was slightly raised
above the surface of the paper and had *small* numbers on it.  

Seems like it was designed to make counterfeiting harder and money
easier to trace.