Do kids under 2 or 3 really eat free?

I keep reading that sit down restaurants, kids under 2 or 3 eat free. Is this real? I don’t seem to recall noticing not being charged for kids meals at the couple of sit down places we went. It was river belle terrace and carnation cafe. If this is still a thing and there are places younger kids eat free, we are going soon w a small group of kids and parents and that would be amazing. Thank you