Hidden Tracks

I used to like when you'd listen to a cassette tape and all of a sudden realize that there was a hidden track at the end. It was a nice bonus... felt like you got more for your money. I've seen CDs do something similar where they'll list 12 tracks, but then have a 13th track that wasn't listed on the case. The thing that doesn't make sense to me is when an artist puts the hidden track after a bunch of blank space on the last track. In a day and age where we rip our music for our portable players, why would you put in about 6 minutes and 15 seconds of blank space between your final track and your hidden track. It's obvious that when the song ends and there are still minutes left on the track that there's a hidden track in there somewhere.