NOT! And it could have been prevented if you'd thought explain to these kids how the toilet works and what not to put into it. They're not born knowing marine toilets can't "swallow" all the stuff they flush on land..You weren't and neither was I...we learned the hard way or somebody taught us.
You really DO need to explain to guests how to flush the toilet, but a lot of people seem to be uncomfortable about how to approach that. The easiest way is to make it just another part of your "this is where everything is and how it works" tour of the boat--something you should do for ALL first-time guests, landlubber or not (how many times have we all had to hunt for 10 minutes for the light switch in the head on a strange boat...and finally had to ask?)--when they come aboard. The toilet just becomes part of the "tour," and showing 'em how it works then is a LOT less embarrassing for you AND your guests than having to show someone how to flush a full bowl. Put a sign in the head in a location no one can miss. When it comes to kids, threatening bodily harm if they clog it may be necessary.
And by the way...I've always made safety issues a part of that tour... "Here are the lifejackets. God willing we won't need them, but just in case, here’s how to put one on. The light switches are located...and they work by…. The water faucets work just like the ones at home, but please don't let the water just run, because what's in the tank is all there is. Please don't try to help unless specifically asked to do something, you could get hurt if I zig when you expected me to zag…" etc. It's been my experience that landlubbers are a lot more comfortable aboard immediately when they know a little bit about the boat, how things work, and what's expected--or not--of them.
