I've had it happen on servers where that moderation option is not enabled. My worst experience was trying to join a friend group's discord via an invite link shared with me. I was prompted to create an account with email, and I did. I was then shown a read-only view of the server: I could see all messages and other folks could see I joined and 👋 to me. I could not send messages myself, however, without verifying with a phone number. Further, I couldn't use a Google voice number (my primary number) to verify, nor my "real" number which was associated to another account.