Maybe the destruction method would be something like UV light to melt the cuffs.
Is it so important that we have re-usable cuffs?
Zip ties themselves are easily circumvented with a razor. If stronger, how much stronger? Do you need heavy-duty bolt cutters to get them off?
UV light to melt the cuffs.
Wouldn't a UV light source then be an easily-producible key?
The crux of the idea is that only way to get the cuffs off is to break the cuff with a specific brute force that requires a large unconcealable device. Even with the device, you still need time/space to use it (5-10 mins).
So pretend that we would need a large UV lamp and 5 mins to melt through.
And they do nasty things like putting your hands behind your back.
Although, those were metal cuffs so I could maneuver my wrists independently.
Party at Pavel's house!