Will a wallet cellphone case demagnetize my credit cards?

Episode 1144 (1:34:54)

Willy from Florence, CO
Credit cards

Willy got an LG Vista and he doesn't like how big it is. Leo says at 5.7", it's ginormous. Nice, but very huge. Willy is considering carrying it in a special wallet case that's inside his pocket. Will the cellphone signal demagnetize the credit cards in his wallet? And will it interfere with calls? Leo says no. He has a similar pouch and neither has happened to him. There are several cases that have doubled as wallets and they work well.