I just had to google about this because i knew it was true but i couldn't remember what caused it but for some women a tumour in the brain or endocrine disease CAN cause the excessive release of prolactin (whether she is nursing a baby or not) and that DOES make her produce excess milk. For that reason a woman who has a very large breastfed infant PLUS other symptoms which might indicate an endocrine issue are screened JIC. So if you are ill, you CAN overfeed a breastfed baby, but limiting time or frequency of feeds doesn't help, you have to get the underlying condition treated. There is no way to overfeed a breastfed baby by simply putting them to the breast when they're hungry.

Bx

ETA - my favourite bad advice was during labour. I needed to push. "Don't push, baby is just posterior, you want to push because of that". Oh yeah, why is her head crowning then?