I read in Unofficial Guide 2009 that they removed this part of the ride based on rider feedback and they really scaled back on the catching poachers theme. It is now more mild for younger children. We were there 2/7-2/14 there was no shaking bridge and only on phone call from "Wilson" to help with the poachers.
The storyline was changed a couple years ago, where the bad guys aren't really "poachers" but rather "elephant kidnappers". I haven't ridden the safari since late 2007, but even after the storyline changed, the shaking bridge was still there.
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