Your boarding pass does contain information about you, but whether it can be used for evil is another question – Los Angeles Times
It was fun sitting with the author poring over her boarding pass and picking apart what everything meant. Though I couldn’t decipher some of the info that popped out on the barcode, there was definitely enough info in there to be able to at least cancel a reservation if not use the credit for something else. (That’s particularly dangerous on airlines like JetBlue where you can use a credit for another person.) In general, I recommend not being an idiot and posting your boarding pass (without redaction) online. If you do use a paper one, it can’t hurt to shred it once you’re done. Chances aren’t great that you’ll run into trouble otherwise, but why take the chance?