No, Splash Mountain does not have any lap bars or restraints. That's interesting that Ripsaw has to completely e-stop at any signs of movement. Whenever a sensor was triggered on Splash, we did a basic ride stop, and sent the person at Unload into the mountain to check it out. Even if the sensor was triggered by a person getting out of the log, the CM just went to them, walked them out of the mountain, and roughed him up a bit (okay, maybe not that third thing). The whole process took 5, 10 minutes max, and then we were back up. E-Stops were typically reserved for someone falling/jumping into the flume - though that's pretty rare - or if a sensor was triggered at the bottom of the final drop where the brake is, and even then it usually only took 10-15 minutes to get the mountain back up. Though if it for some reason took 20+ minutes, we evacuated and then did the reset.
I worked at Splash Mountain last year for my CP. During my first day of training while in tower, a woman jumped out of her log at pre-C onto the left side. She then saw there was no exit, so she tried to jump over the flume to the other side and fell in. Imagine my horror as my trainer starts yelling over the speaker and hits the e-stop. She ended up getting out of the flume just in time and ran all the way up to the top of C lift. Why anyone would do that if they were scared is beyond me, but at least she was okay. Regardless to say it was quite an experience for my first day!