People don't store their spinnaker or whisker poles vertically on the mast because when they work loose (all by themselves, it just suddenly happens!) they drop down and (pick any two) 1/hit people who are sunning on the foredeck, causing a 4" gash that leaves bloodstains that are a real chore to clean up 2/hit the deck, causing a 2"gash and cracks that cost $1500 to fix 3/hit the hatch, requiring a new $800 hatchcover, 4/ torque and break the $300 end fitting, the $100 mast fitting, and possibly the $100 track, which will cost $750 to re-install. If you calculate how long the pole is and how much leverage that affords at the business end, you will probably stow your whisker or spinnaker pole on deck. If it is too heavy to handle, each of those pounds is adding to the leverage and/or impact of the pole. Perhaps carbon fiber would be a lighter option. Despite its cost, it may end up being cheaper than the alternatives.
With all due respect, I think you've been reading too much Stephen King!.
Of all the problems I anticipated, having the pole come loose wasn't one of them. Anything this important on my boat doesn't "suddenly work loose all by itself"! For example, my jib sheets seem to stay tied, and they are under a lot more stress than a vertical whisker pole would be. Currently, I have secured the upper end of the pole with a bowline in the topping lift which is tied through a hole in the pole's hardware. Could this fail? Highly unlikely, but theoretically, yes. However, I think there are about 50 life threatening things that are much more likely to occur every time I sail, i.e., MOB, accidental jibe, through hull failure, etc., etc.. If I was that worried about them, I would have to sell my boat. After all, despite the best preparation and maintenance, there are many safer hobbies than sailing!
Anyway, back on topic. If I install hardware to hold the pole, I would still use the topping lift (or some other method) in this manner to provide redundancy, unless I was convinced the hardware was absolutely bullet proof. BTW, in the scary list of options you gave me, you left out the most expensive. That would be the Million dollar law suit the sunbather with the 4 inch gash in his/her head would rightfully bring against me for my negligence.
Maybe I could counter sue for those pesky bloodstains in my deck?