If you watch the judging from that season, it’s clear Judy did not vote to bring her back into training camp. Because as you said, Judy knew she could never handle the choreography. My interpretation was the other judges kept voting her in because she had a great look and figure (some one mentioned Julia Roberts as a look alike). Other judges don’t care as much about the dance ability, especially in the earlier seasons. Ratings could definitely come into play, but I’m one of those people that naively believes production doesn’t have as much influence when it comes to who makes camp.