Ah, finally got what you mean by "robbers knot". I know it as Highwayman's Hitch, which isn't in any way a better name for it, but just the one I encountered it under. My preferred use for that is in docking.
Several docks in the area, including at my favorite restaurant, use "railings" along the edge of the dock for tying up, instead of cleats. Passing a bight under the railing and locking it with two interlocking slip knots gives the robbers knot. Not something I would use overnight, but if the slip knots are locked well, the knot won't come undone easily, other than by tugging on the free end. If worried, you can add any number of additional slip knots
Even, so, I usually get a table at the window
I don't really have a worked out strategy for heavy winds, they just aren't that common during the summer here. I can also reach all the way to the forestay with a paddle while standing in the cockpit, which is my go-to method for getting the jib all the way down (prior to docking, for example). I don't have the type of hanks that could keep a downhaul captive when not rigged and I rather not clutter up the boat with additional lines. If I did, I would go for a line tied to head and clew, held captive in the hanks, and with a small micro block lashed to the tack (not to the stem fitting). That would then be permanent part of the sail. It would be operated by reaching to the clew and grabbing it there. But as I don't have that type of hanks, that's just a design idea. While underway, the line would be kept tight by sail tension. I was thinking something like a 3mm or 4mm Amsteel would be nice and light for the purpose.