The answer is that social media platforms such as Snapchat take great satisfaction in being the forerunners of user privacy and security. When it comes to ensuring that the integrity of their user's Snapchat account is never compromised, they deploy powerful encryption and security firewalls.
In the case of Snapchat, for example, it is not permitted for casual users to access two IP addresses at the same time. If Snapchat detects a user logging in from a different device, it immediately sends an email to the user's linked email ID and contact number, making it exceedingly tough to hack into.