ok...
There is actually a very good reason why this has happened
The actual design of the jumping stilts is covered by a
Patent in most countries, this means that they can only be sold
LEGALLY by people if they pay the inventor a fee for each jumping stilt they sell. Which is totally reasonable if you have designed something cool and others are going to make a profit selling it - then surely the inventor should also be able to benefit from that too?
The stilts you see being destroyed were ILLEGAL, therefore customs seized them and destroyed them so that it would mean that the seller was not making unfair profit and secondly it acts as a warning to other illegal sellers.
Pro-Jump stilts are legal and patent protected, as Pro-Jump pay a fee to the original inventor and are therefore LEGAL.
In fairness, although it's a shame that the stilts were destroyed I think it was the right thing to do in order to protect sellers like Pro-Jump and others who actually pay the Patent Fee and also to Alexander Bock who invented such a great gadget!
The other alternative would have been to give them away to charities, however it's a hard one as if the brand is unknown then who would be able to vouch for the quality?
