Learned something new today, reading about these in more detail (e.g.; tendency toward physical deformities (musculoskeletal), etc.
Many thrive, reach adulthood, breed...so it's not simply a case for a hunter, for example, of 'see one, cull to make the herd more viable' (and I'm a little hazy on the ethics of that, besides...I'm not a hunter, but the thought did occur). And a piebald can sire or give birth to 'normal' fawns (double-recessive gene), so there's no 'certainty' about passing on to offspring - it's a genetic anomaly, not a disease, after all.
Not as rare as true albinism, but as mentioned, about 2% occurence...so pretty rare & indeed special to see.