Yup, Mark has been distributing his MET showings in the clear using regular MPEG2 for many years now, both in the US aswell as internationally. In the US primarily shown on a pre-show network/system. Overhere they use Barco DP-100s, and in Scandinavia it is a mix of DCi set-ups and lower grade systems in community houses.
As his various SPMTE presentations point out Opera is generally the first to use new (broadcast) technology, like subscription cable, or motion pictures with matching sound way back in the nineteenth century.
In the old days there was this French service that distributed Opera and Dance and other (high-)culture performances in HD-MAC. Once a month to periferal locations. Production values (budget) was reportedly low, but it was HD, they since moved to MPEG SD, not sure if it still exist.