You can vote illegally in any European country, but Norway probably has the best system for this. You see, most countries will keep statistics of persons who enter the polling station without voting rights. They will not be able to submit a ballot but it is documented none the less. In Norway you will actually be able to submit a ballot, it will be rejected at a later stage, but you ballot exists and it is a part of the results of the election, even if it won't count as a legitimate vote.
First Illegal Vote