You don't have to vote, Van Geel, you can still vote 'blanco'. The only obligation there is, is to go to the polling station, so nobody can keep you busy to prevent you from voting.
So there are things to say for it, but of course, it does look a bit silly...
Nobody goes to jail anymore, if you don't go to the ballot, most judges don't bother. People who were selected as chairman (you have to be able to read, so they mostly pick out teachers

) or vote counter who don't show up without a good excuse, are prosecuted, but when convicted, they just get a fine...