Wow, that's one hell of a law--in a silly, brainless way I mean.  I'm not dissing Australia, mind you, because there are just too many laws worldwide and way too many that don't make sense.

What's been said is true.  Nobody could verify ownership unless they produced an identical seed word list/private key without first seeing yours, and if they knew what they were doing they would have already imported that key into a wallet and transferred the funds, thereby making the paper wallet you found useless.

I've read the suggestions about trying to return the funds and find the owner of the wallet...but personally I wouldn't even bother.  You'd be opening yourself up to all kinds of security risks and hassles from who knows how many people.  IMO it'd be better to just quietly move those coins to your own wallet (after learning a little more about bitcoin).

I doubt the cops would ever find out if you just used the funds on the wallet you found.  In crypto, it's basically finders-keepers in situations like this.  But man, I do admire your honesty!