Yes people have a tendency to godify the "tax authority" forgetting that at the end of the day it's just people hating their shitty who don't give a fuck about you.
As long as you are not Al Capone or Ben Laden you'd be ok if you are more than 70 IQ
The only thing with Bitcoin is that as it's a public ledger you can't say that you lost the keys if the coins are still moving.
You have to declare them stolen and then live out of it like your friend