I predict that by day 1 of operation someone is going to turn left into an oncoming LRT. I work near the Golden Mile and the drivers here (well, everywhere really) are atrocious. Lots of people don't realize (or care) that left turns are on a separate signal, and turn left as if they were traditionally signalled intersections.
Now I'm pessimistic by default, hopefully people will learn quickly but honestly arms might be a good idea to prevent drivers from pulling in front of the trains while attempting a left turn- this could potentially allow trains to travel at higher speeds through the intersection too. I know neither of these things are on the table at this point, but we'll see what happens after a few morons get creamed as they turn in front of a 40 ton vehicle.