I tend to turn a blind eye towards it unless you can audibly hear them chanting the words "like" and "totally" and "omg".
If they are taking selfies for:
1. A scrapbook of visited places
2. ???
3. !?!?!?
Then I'm fine with it. Other than that, it's not practical and is more of an impulsive, security breaching* and vain habit, especially if you're addicted to social media.
*metadata