The Des Moines Register has a thoughtful article on the trend toward incorporating religious symbols in personal adornment from jewelry to tattoos.  As the author notes, wearing articles of faith does not necessarily mean a person is religious.  Says one pastor:

"It's ironic that the cross is a symbol of self sacrifice and as it is embraced in popular culture it is becoming a symbol of overindulgence, luxury and success." . . .

"For a segment of our society, everything is value neutral. That's completely the opposite of what we need to do," Hibben said. "There's going to be a tension between the cross of faith and the cross of consumerism, which is contrary to the Christian message."

And a rabbi agrees:

Rabbi David Kaufman of Temple B'nai Jeshurun, 5105 Grand Ave., said it's disrespectful to buy and sell spiritual symbols for their beauty or design.

"Jews believe that people should respect the religious traditions of others, no matter what the religion," Kaufman said. "When fashion and celebrity turn religious symbols into a fad, then there's a problem. People should wear religious symbols because they believe in it."

The commodification of faith in fashion is a classic example of cultural appropriation, the subject of law professor Susan Scafidi's engaging book Who Owns Culture?, featured up in the left sidebar.  You can also find more on this topic in BootLegacy, an informative new cultural property blog by attorney Elizabeth Nevis.