Many carriers say you will have to or you might have to show the credit card, but in my experience they almost never do, maybe once in my last 20+ trips to/from/within Asia for me.

A few years ago I bought a ticket for a friend on Thai. It was a one way ticket between two countries, using my credit card from a third country for someone unrelated to the passenger, which probably raises as many red flags as possible.
Not wanting any problems for my friend later, I print and fill in the authorization form that the Thai website provides and says I need, then bring it to the local office a few days later when I'm in the city. Once I'm there, I'm told "Oh, we never check that for tickets originating in Japan. You're fine".