if the manufacturer knowingly distributed them . An error is something different that's made unintentionally. The concept of collecting errors depends on the maker taking pride in producing a high quality, error-free product.

The US Postal Service used to make stamps of very high quality and without errors. When they inadvertently produced 100 of the inverted-airplane stamp in 1918, it was an error, and was highly valued by collectors as a rarity. When they REPRINTED 100 sheets of the same stamp last year with the images on all the stamps inverted, it was no longer an error, it was a "limited edition" made to be collected.