Isn't there some sort of diaper etiquette?

So this morning, Will and I were at gymnastics. We had just finished our warm-up and were at our first station, an obstacle course with a tunnel and a slide and a ladder with a bell at the top (which Will reached and rang for the first time today). I suddenly smell the distinct smell of a dirty diaper.

At almost the same moment this mother, who I already find annoying with her constant commentary on her child, announces, "As soon as we're done, we're going to have to change that diaper."

Okay. I guess. There is still another obstacle course, the pit filled with foam squares, and the trampoline. If you want to wait until we're ready to move on to the next station, that's not too terrible, even though the smell is getting worse by the minute.

But when we move over to the next obstacle course, she and her son come with us immediately. I make sure Will isn't right behind him on the balance beam, trying to avoid the odour trailing out from behind him like smoke from a steam engine.

It's in the pit that I start to get worried. I mean, it's one thing to make your poor child sit (stand, run, crawl, tumble) in a dirty diaper. It's another to allow the stench to permeate the air during a class with other toddlers. But it becomes an issue of sanitation when your son is rolling around in the foam pit with this diaper, that could leak or explode at any moment.

It gets worse on the trampoline. I can acutally see the diaper, weighted-down with poop that's at least 30 minutes old, sliding into the child's pant leg.

And I could hear the mother laughing: "Poor guy. Look at that diaper." Um, yes. Look at it. And do something about it.

I was disgusted. Of course, I didn't actually say anything. I just kept Will as far as possible from the line of fire. But under what circumstances could this be considered appropriate behaviour?

Just where do you think you are, lady? When you are participating in a class - especially one that involves a lot of movement and bouncing and shifting of clothing - take some responsibility and change your child's diaper. Immediately.