Yes but that's only relevant if you're aware of a specific community on a specific instance and expect to be interacting with it on purpose.
It's completely irrelevant if someone just gives you the name of an instance, tells you to make an account on it and start using. You'll be perfectly fine reading and commenting whatever's in your feed.
The only way this breaks is if you're in an instance that is too small to have local traffic while having technical difficulties with federation. If the instance is active enough or it's federating normally, someone completely unaware of the concept of federation will be perfectly fine as long as they understand the interface.