He didn't hide the watermark; he framed it. He added a note in the corner of his presentation:
18;write_to_target_document7;default0;992;0;a1f;0;6f0;18;write_to_target_document1a;_8eTuafvEK-uIwbkPo_O86Q8_20;f21; Common "Workarounds" (and Why They Are Risky) remove vectorworks educational watermark better