Vurbano, I'm not trying to refight the holy war. My opinion is just based on the things I read through here:
http://www.avsforum.com/avs-vb/showthread.php?threadid=323602
Essentially, both 1080i and 720p have 60 million unique pixels drawn every second.
The thing is, 1080i is not really shown at 1920x1080, but at 1440x1080. I have to take the number crucnchers word for it over there, as I don't have the equipment. But at that diminished resolution, 720p takes more bandwidth.
However, like your point says, 720p is more forgiving of compression. Compress 1080i too much, and you get the artifacts. Not so with 720p. I guess this is what your TV station is doing. I also think my initial hypothesis was wrong. I'll believe Wilt. If they were trying to save bandwidth they could have just compressed 720p more easily than 1080i. So I'm an idiot, but at least I learned some new things.