It's in my post that I have 4' semi-modular sections, so permanently taping them was not an option. This layout has been moved three times across two states. With the 3/4" separations back to back of 2 sheets, they mesh together like tongue and groove at the joints, with a screwed-on wood lateral reinforcement across the top edge to hold everything tight. But everything expands and contracts, really - rail, tables, backdrop, etc, and despite all manner of filling and caulking with flexible material, a hairline crack reappears every year.
When I'm doing photos, a clone stamp in Photoshop solves the visible crack problem nicely....