I don't think so, typically, most Hi-8 cameras, run tape at 15 fps. Broadcast typically utilizes a 60i (sixty interlaced frames per second) format.
If Hi-8 has been used before, it must have been processed in an awkward way to get it through broadcast. Given today's advancements in DV and HD, it's questionable as to why someone would intentionally want Hi-8 for broadcast.
It would be kind of cool though to see that format in broadcast...the harshness of it, it's choppy feel, blown out and grainy, could be interesting from a creative perspective.
If such a broadcast materializes, I'd like to know where and when I'd be able to see it... 8)