Is it safe to use a Tripp Trapp® Baby Set without a Stokke® Harness?

Of course! That is what we recommend.  

Although not in line with the Tripp Trapp® seating philosophy, Stokke offers an optional harness. The Stokke® Harness should only be used with the Tripp Trapp® Baby Set. Never leave the child unattended and stay within's arms reach. When the child can climb up and down the chair independently, the Baby Set and harness should be removed.