91,000 "boarding pass" and 42,000 "concert ticket" search results on Instagram - not all may include bar codes, but that number is significant considering what you are putting out there.
Mobile ticketing is a safe (and tree friendly) way to go.
But then, there are those third parties we need to worry about.
In What’s In a Boarding Pass Barcode? A Lot, KrebsOnSecurity told the story of a reader whose friend posted a picture of a boarding pass on Facebook. The reader was able to use the airline’s Web site combined with data printed on the boarding pass to discover additional information about his friend. That data included details of future travel, the ability to alter or cancel upcoming flights, and a key component need to access the traveler’s frequent flyer account.