Never go to any of the US-allied countries if you owe tax money to the US. The outcome wouldn't have been any different if he had visited Portugal or Germany instead of Spain. They caught the btc-e CEO in which country? Greece? They can get you anywhere unless you are in Russia/China.

The better solution is: don't get indebted to the US.

Al Capone couldn't get away, McAfee couldn't get away. You won't get away too.