I painted a windowsill yesterday with white gloss paint, half an hour later there were four perfect white cat footprints on the dresser, and a nice trail going down the stairs, across the kitchen floor, a flurry of them under the kitchen table, and a slightly harried-looking cat on the back doorstep. 
I cleaned her paws off with some wipes (PowerForce MultiTask Wipes from Aldi, in case anyone else needs them, they are fab), washed them and let her out to sulk.
Today, DD noticed her bum. It's white. And dried-on.
I swear I didn't notice it yesterday!