Can't say I have ever used "bad oil" I was a Valvoline guy in my younger years (Mark martin fan), then switched to Castrol, then Mobil 1 and now a significant amount of Super Tech.
As a teenager I worked at a gas station that we kept all the used bottles of oil sold to customer's. We flipped them up and drained them into a gallon jug. This oil was then put in a used 1 quart container and given away to customers that needed oil but couldn't afford it. I guess this was my first experience with "frankenbrew"
Just my $0.02
The first full service station I worked at did this too. Back in the cardboard can and spout days. We had a pan in the garage area with chicken wire over it and turned the cans upside down for that last oz or two to drip out.
We didnt give it away, it went back into a oil can for topoff. and we charged for topoff.