According to Business Insider, when it comes to interacting with the public, there is certain protocol that the royals have to follow.
One of the rules includes no physical contact with fans, which has been broken in the past by Kate Middleton and Meghan Markle.
But one rule that you won't see them break is the ban against taking selfies with fans.
Although Buckingham Palace has not confirmed the rule, Meghan Markle once told fans: "We're not allowed to do selfies.