I remember from the arcade days, operators would paint quarters for testing so they could remove them from the revenue share numbers. Maybe this was a sort of s

I remember from the arcade days, operators would paint quarters for testing so they could remove them from the revenue share numbers. Maybe this was a sort of shibboleth? Greshams law says bad money displaces good money, so a lower value coin would let an organized operator pull silver out and know their own. More likely just an error, but possible?