Not that it helps but they do the exact same thing in Australia most of the time. Here the FTA providers have a SD channel and a HD channel. If the HD program is exclusive to HD and not shown on the SD channel, the watermark will not be 4:3 friendly usually. That's about the only time they get it right.

For sport they do the same thing. Looks quite stupid and for anyone who hasn't really seen 16:9 before I have to explain why they do it.

A couple of channels have had watermarks so large or intrusive recently that after backlash from the public they were made smaller and/or more transparent. Surprising since they generally don't listen to what the public want. One of the channels was the ABC which is the government owned broadcaster.