It's happened to me---except I didn't catch on right away. I kept sorting my own pennies and getting very excited, until about 10 rolls into my own stash, I noticed that big pile of Brinks-wrapped pennies.
Topic moved to Hoarding Copper Pennies section.
"Bart, it's not about how many stocks you have, it's about how much copper wire you can get out of the building." --- Homer Simpson
When I do reroll the coppers it by machine and a custom label proclaiming them as COPPER CENTS is put on each roll. I have never had any problem confusing these with CWR.
If your percentages are low.. just sort more. If your percentages are high.. just sort more.
Now selling Copper pennies. 1.6x plus shipping. Limited amounts available.