We had a picnic on a beautiful warm day last week (yes there was one)with several generations of the family.All the food spread out on a huge tablecloth on the ground.,Daughter in law proceeds to move a few plates before changing (very smelly)six month old's nappy on it.She has a habit of doing this-my living room carpet,kitchen worktop,my bed-never with a changing mat.There have been more than one occasions when I've had to clean up afterwards-not huge marks but still a bit off putting.I've bought her a couple of changing mats,including a folding one that's easy to carry when you're out but she never uses one,even in her home.i've noticed marks on her upholstery and carpet in her own house.I don't want to say anything but it's not very pleasant for anyone else.