A thought on rubber bands if you use too few but enough to hold the wing on, the plane will tend to zoom with positive G, because the wing will actually lift off the mount causing large positive incidence momentarily (top winged models). I've actually seen daylight between wing and mount during flight on rubber band mounted wings on trainers. Easy fix.

After learning how to fly, I did that on purpose to play around with zooming of the plane at its own whim an not mine

One thing I've found with velcro straps is they need replacing after about 100 uses. Turns out the hooks apparently get straighter over time and yarn loop ends frey, and they don't hold as well. It's a simple replacement.

On plastic bolts used as hold downs, I did a strength test on a single 1/4 -20 nylon bolt many years ago. This was a standard test using an Instron Extensometer. I was surprised to determine that one 1/4-20 nylon bolt starts deforming at around 80 lbs load, stretches threads at 120 lbs load, but doesn't break the bolt until about 150 lbs. A single bolt is strong enough for many wings, but I'd use 2 anyway. Have also used a pair of smaller bolts such as 10-24 and these work fine too

If you definitely want the wing to come off on hard landing, forget about rubber bands. The easiest way to do that is with a snap on spring loaded set-up. A spring loaded wing installation takes two seconds to put the wing on or take it off. Set up the springs so that dowels are pushed in as the wing is pushed forward, and then let the wing slide back into its rear dowel socket. It's actually a very simple set-up and its great on trainers