I'd be fine with doing it the way Boston does it.
Maybe I need to be more specific. We're talking about the maps that the TTC will be using in our subway and LRT fleet. For example, the Subway/RT Route Map in cars today.
Of course the TTC shouldn't be putting the LRT lines on a subway map. The only three subway lines in Toronto are Sheppard, Yonge-University-Spadina and the Bloor-Danforth. However, the TTC hasn't publicly used subway exclusive maps for almost 30 years. The closest thing they have is their "Subway/RT Route Map" that are used on our subway fleet. It features our SRT, BD, YUS, and Sheppard lines. The SRT is not a subway. They switched over to that map when the SRT opened in the 80s. I see no reason why they won't do the same now with the LRT. Especially since TTC/Metrolinx have been pushing it as a cheaper, but fast alternative to expensive subways (which is exactly what it is).
Who would it be misleading and how? It's not like these things are bus/streetcar routes, where it can literally take 30 minutes to travel 1 km. These are LRTs which in practice should have a trivial speed difference when compared to heavy rail.
What's misleading is omitting the LRT lines and making people falsely believe that there's no transit in those areas.
Imagine the complains when thousands of customers spend twice or three times as long as they need to travelling because someone decided that LRTs, which are almost as fast and operate nearly identically to subways, weren't good enough for our Subway/(L)RT Route Map.