While I don't think that I have ever watched the Baby First channel, that is interesting. It is a regular 720x480i signal, but it displays as widescreen. It is an MPEG4 signal, so most SD only customers can't get it.
You have to keep in mind that aspect ratio and pixel resolution are actually unrelated unless "square" (1:1) pixels are used.
Though by keeping the horizontal pixels at only 720 while stretching them out to cover a 16:9 image will naturally cause a proportional reduction in the horizontal resolution PQ.