In general, there is no good reason to provide anyone with your booking code or confirmation number (or whatever your airline calls it). The only purpose of this code is to check-in, rebook, cancel, or otherwise mess with your flight, and nobody besides you should be doing any of those things.

Sharing a photo or the details of your flight ticket (specifically your boarding pass or booking confirmation) online is highly unsafe and can lead to significant security risks. Your flight ticket contains a Passenger Name Record (PNR) code—a six-character alphanumeric string—which, combined with your last name, allows anyone to log into the airline's "Manage Booking" portal. From there, a malicious actor could cancel your flight, change your seat, or even access your sensitive personal information, including your passport number, date of birth, and contact details. Furthermore, the barcode on a boarding pass is not encrypted; simple apps can scan it to reveal your frequent flyer number and future travel plans. This information can be used for identity theft or to target your home for a burglary while you are away. If you want to share your travel excitement on social media, it is best to post a photo of the plane, your passport cover (with the ID page hidden), or a blurred version of the ticket that completely obscures the PNR, barcode, and ticket number.