
A Star Destroyer carry twenty AT-AT walkers, thirty AT-ST scout walkers, and 9,700 ground troops; there were at least two in orbit over Tattooine, plus they would have spared no expenses finding those droids
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Fri 10 Apr 2009, 21:03,
archived)

after intercepting Leia's ship. Plus, those troopers shown on dewbacks might be the regular stationed troops who use dewbacks all the time so stick with the transport they know works. The outtakes might feature loads of walkers all over the planet slipping and sliding about in the sand.
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Fri 10 Apr 2009, 21:08,
archived)