"If you do, why" is a better question. And frankly, neither version really tells anyone anything.

People don't check largely because Lemmy UI isn't designed for the community to be a prominent thing, and being a member isn't required by the app for someone to reply.

I assume this is being asked because of the earlier thread about "read the community rules before posting"... As someone else already said, make it private if you don't want the public responding.