My friend was asked to sign a waver that the next flight isn't back to Thailand. This was asked by Air China at check in on the Thai side.

She's now in China considering to still use the return ticket or not. The return ticket was also bought before the signing of the waiver.

Sarcasm, really?

Why do you ask?

Has your visa expired?

I read some here requested an extension after overstaying a few days and paid fine but got the extension as well.

Ah yeah, that's what I mean.

With all these different countries and different rules and terms I've mixed them up.

Like Lyondon said.

If you needed to get a visa before arrival, then simply request a new one. When you're able to get a visa on arrival, then just go and come back. It will be treated a s new entry with a new date.

I was here on a visa on arrival in September, which gave me 30 days.

Went abroad, came back a week ago, and got a new visa on arrival with 30 days from the latest arrival.

Just bring your ticket from your flight in to Thailand, they register the flight number with you entry.

Depends on the customs if they have doubts or perhaps certain nationalities are always asked.

For example I have a Dutch passport and gotten in twice without being asked for forward ticket, and without a visa in advance so on arrival.

They do want to register your incoming flight, so keep your boarding ticket from the flight you came in with.

Another example it depends on you.

When I flew from Siep Reap Cambodia to HCMC Vietbam the airline check in clerk asked the person in front of me for a forwarding ticket, but not me. 🤷🏻‍♂️

To be sure, you can get cheap fake airline tickets for just over 10 USD or so.