There are a couple of special cases for when you don’t have a VSchema in place.
For example, if you add a table called foo to an unsharded keyspace called ks1 the following routing will enable you to access the table:
USE ks1; select * from foo;
From the unqualified schema using select * from ks1.foo;
As long as you have only one keyspace, you can use select * from foo in anonymous mode
However, if you have more than one keyspace you will not be able to access the table from the unqualified schema using select * from foo until you add the table to VSchema.
For a sharded keyspace will not be able to access the table until you have a VSchema for it. However, you will be able to see it in show tables.