The "Kids Getting Into Stuff" Equation
When the kids are getting into something, and enjoying it, sometimes it's worth just letting them play and explore the world on their own messy terms. Here's how to know when to interfere and when to let it slide:
If F (how much fun the kids are having) times L (how long it will keep them entertained and out of your hair) times N (whether or not they know it's naughty, where N is a sliding scale from 1 to 0 with 1 being completely innocent play, and 0 being "Mom just told us not to do this three minutes ago, and we fully understood") is greater than C (amount of time and effort it will take to clean it up) times D (likelihood of irreparable damage or bodily harm), then just let them play, and deal with the mess later.
If FLN<CD then intervene
If FLN=CD then the only logical course of action is to join in. I bet smearing soap on the bathroom walls really is just as fun as they are making it look.
I'm sure my equation has mathematical errors. This is just a blog, not a web comic.