I wouldn't mind a child of mine participating in a contest like that. I admit I find the contest a bit freaky, but it is still a challenge and I would support my kid for standing up to the dare and wanting to win it.
I think it was a cute contest for kids. I know my cousin's little boys would love to take part in something like that.
Now admittedly if it was my kids, (note I don't have any children yet), I would make them house their sneakers outside so I would be stunk out of my house but I would let them enter the contest if they wanted.
If my kid entered that contest, she'd win. Who cares if it's to be the stinkiest feet? It's a contest, they're kids, and it's something fun. And it grosses out us adults, which is the most fun thing a kid can do.