It probably depends on where the zipper is located - across the shoulders or lower in the back?Zipper in the back??.........I can’t image managing something like that behind my back and out of sight - trusting it shut tight at the end.
I was worried that I'd have problems with the mid-back zipper on my Level Six Fiord suit but it hasn't been much of an issue. There's a long elasticated pull which helps. That said, I did remove the (cosmetic) covering flap over the zipper as I was aftraid I might snag it when closing the zipper - that would certianly be an issue if travelling solo.