Groovee-
Are you serious? Splash is one of the most popular attractions and just because this has happend twice in the 14 years it's been opened you're not going to go on it? It hasn't happened in years. YOU ARE SAFE! What do you think goes on during park close hours? Maint. comes in and inspects that thing to a T.
The flume itself isn't that deep. But there are spots that, yes, the water could crest the top of the log. In some spots it's around 6 feet deep (like the part after Drop 1, or what you'll recognize as Slippin' Falls) so it would be possible to sink there.
Also, one time while I was working there the pumps stopped working and all the water in the flume drained out in about 15-20 minutes. We had to evac the entire ride and people had a pretty fair jump out of the log. It is deep enough to sink.
When you're on attractions, anything and everything could go wrong. But the maint. crew at Frontierland is top-notch. Every few weeks the rubber belts are replaced, whether they need it or not. All in the name of safety.
Just because this freak accident has happened does not mean you shouldn't go on Splash. It's a silly reason, really. Just go on the attraction. Trust me, everything will be satisfactual.
And I don't think this thread should be turned into a scientific debate. Since I worked at Splash I know a lot about that attraction. Notice I didn't say everything, but I do know a lot more than the average Guest thanks to extensive training and a 101 question exam I had to pass with no more than 5 questions wrong in order to work there. The CMs at the attractions know what they are doing.
The bottom line is that if you're child meets the 40" requirement, or 42" at Space or 48" at Roller Coaster, they are 100% fine. They will not fall out of the log. You will not fly out of the log going down Drop 4.
The only thing that will fall of is your hat if you don't take it off before Drop 4. And no, there's no magical place where all the lost hats congregate at the end of the night.