Prime examples from my time in the Borg where JWs stuck to the letter of the law (without actually thinking about the point behind the "rule")
1. Fast forwarding through violent or sex scenes in movies but watching the rest of it. Either decide that the movie offends your conscience and avoid it entirely, or watch the whole thing properly (i.e. in context - oh but that's right, JWs just chop out the bits they don't like in the Bible too).
2. Another time a sister came to a cong. BBQ in what seemed like a very short mini skirt. When she turned around though, it was really a pair of shorts that had a flap over the front to make it look like a skirt. I remember she was very pleased with herself, because shorts were okay, minis were not.
It's like they want desperately to follow the rules and conform, but part of them realises that this isn't compatible with real life. So they find these loopholes to salve their consciences.