Answer: The ties you encountered are indeed placed on the plants to keep them becoming damaged during shipment. Sky Pencil Holly branches have a natural upright growth pattern. They should not sprawl out or flop over, but they can bend down if they are watered from overhead, or if wet snow accumulates on the branches. I'm not sure why the one you untied is flopping downward, but I would certainly try to discourage such a habit. Retie the holly so the branches are upright once again. You can use jute twine (available at garden centers) and wind it around the lowest branches (working in among the branches and foliage to disguise it if you wish). Leave it on until next spring. By then the bark on the branches should have matured enough to become rigid and hold the branches upright without support. I'd untie the other two. If they stand up on their own, great; if not, you can retie until next spring.
Best wishes with your landscape!
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