She does look suspicious.
Ok, so the story of "Sunday Surprise", don't know how much is a tall tale and how much the truth, also can't remember if it was at the boarding barn in Montana or Colorado (think it was in MT), anyway... The story goes, owner didn't know her mare was pregnant, checks on mare one Sunday morning and surprise there was a filly in with her. They had come from California, and they believe a mustang stallion jumped the paddock fence and bred their mare, then left the same way; they did know there was a mustang herd in the vicinity of their property. So, if there is a will, there is a way.