Even when I am driving, I don't trust turn signals unless I see concrete action demonstrating that the signal is actually signaling the drivers intention. If the signal says you are making a left turn, I'll wait at the intersection until I see that you are slowing down to make that turn (which means I will often be waiting longer than if I just assumed that left signal=left turn, but it also means I won't get T-boned). I have seen it happen way too often where people are signaling for many miles (or blocks) without making a turn or a lane change, or people not signaling at all (although, I have been guilty of these things on occasion myself). At the end of the day, in my mind turn signals are an indicator of what a driver MIGHT do.