I think this is an American thing because I've never come across any 4:3 DVDs where the original source material was 16:9 or greater. AFAIK in the UK pan and scan died with VHS. The episode that were broadcast in 4:3 I'd expect to be on DVD in 4:3, and the ones broadcast in 16:9 I'd expect ro be in 16:9 No DVDs aren't usually exactly 16:9 because the equivalent ratio use in movies is slighty wider, but TV programmes are made in 16:9 so their DVDs will be in that ratio.