That's really extreme. There are definitely better ways to manage it. Tiktok in Singapore has been very thoughtful in their approach which seems to be working.
Extreme is my view to ban all social media as useless and dangerous means to keep people watching dangerous content endlessly just to show them advertisement s to make them feel inappropriate and buy their self confidence, probably just banning social media for under 21 is quite weak but at least is a start
If it's large enough they may pick it up - I wasn't allowed to board a flight once because they found a powerbank in my suitcase.
I got stopped at security and was shown my luggage. After removing the power bank it was all good, luggage was put onto plane and I was allowed to board.