My devout JW mother-in-law did jury duty awhile back and it wasn't a secret or even a big decision. I don't think she knew she had a choice - she didn't want to do it because it was sex-related (and she is very squeamish) but there was never any concern over the religious implications.
Although, the more I read, I think their congregation is more liberal in a lot of things, such as meeting attendance. Most of their young married dubs only come once or twice a month and are still considered good associates. Go figure. So maybe jury duty isn't a big deal. The good aspect of that, of course, is that they do not zealously pursue inactive ones. :)
SLM