$100 bills are now as common as McDonald's burgers. I remember when if you had a hundred and pulled it out of your pocket people looked at you twice.
As a kid I still remember being in Macy's when a gentleman looked to pay for some clothing items with a $500 bill and the clerk soon became sorrounded by a bunch of gawkers who had never seen anything like that before.

It is my understanding that one of the main reasons the The Bureau of P&E doesn't issue larger notes is becasue of drug trafficiking and money laundering.
One might think counterfeiting would be the reason, but you can believe those bills would get a second look everytime so that might be one of the last things on the list of considerations