Question : This is a (possibly stupid) question about indicating, but I cannot find a definitive answer.

Should you indicate if passing a car on the right (for example, when they are stopped to make a left turn)? At a lot of intersections, a single lane become two or more lanes, so passing the left turning car on the right would require a lane change, in which case I always indicate.

However, on some less busy roads it remains a single lane, but wide enough to still have room to pass on the right if there is a stopped car waiting to make a left turn in front of you.
I indicate to the right to let the driver behind know that I’m about to veer right to pass the left turner. Do you think it’s necessary? Sometimes I think it might just cause confusion too, as they might think I want to make a right turn?

First of all there is no such thing as a stupid question.

Second, YES (…in my opinion…) I think this is necessary to indicate. Remember the reason we signal is to tell others what we plan to do. How is the guy behind you supposed to know if you are planning to also turn left, stop and wait patiently for the car to turn left, or turn right, or go around? Always do a quick signal before you move (not at the same time) (maybe just a few flashes of the signal light) in this situation to indicate you’re going around. Also, you should do a quick mirror and shoulder check (there may also be bikes).

Even though you may be travelling on a road with only one lane in your direction, if there’s enough room that you can safely go around a left turning vehicle, treat this simply as any other lane change here as the only thing possibly making this not an official lane change (2 lane changes actually) is the absence of the little white lines on the ground. Otherwise, it is simply a lane change, and another lane change, is it not?

So, do a mirror/signal/shoulder check before you go around and do another mirror/signal/shoulder check before you go back into the normal lane. This is to make sure no vehicle behind you has moved into your blind spot and/or the left-turning vehicle hasn’t decided he is tired of waiting and actually doesn’t want to turn left anymore & is randomly now continuing straight on (which is of course highly not-recommended behaviour, but it could happen right?)

You are correct in that you don’t want to have the people around you think you’re actually turning right when you aren’t, as this could lead to all kinds of other disasters. So just make the signal early enough and quick enough and turn off the signal before an opposing left-turner would be confused by it.

Realize too that the left-turner in front of you is now blocking the view for the potential left-turner facing you, so go through the intersection with caution. Slowly may be a good idea in many cases, especially when there is a considerable gap of space in front of you which may lead the oncoming left-turner to assume there may be nothing coming anymore i.e. a good time for a T-bone collision. 

GoAroundLeft

British Columbia Motor Vehicle Act:

Passing on right in the BC Motor Vehicle Act. (MVA).
158 (1) The driver of a vehicle must not cause or permit the vehicle to overtake and pass on the right of another vehicle, except

(a) when the vehicle overtaken is making a left turn or its driver has signalled his or her intention to make a left turn,
(b) when on a laned roadway there is one or more than one unobstructed lane on the side of the roadway on which the driver is permitted to drive, or
(c) on a one way street or a highway on which traffic is restricted to one direction of movement, where the roadway is free from obstructions and is of sufficient width for 2 or more lanes of moving vehicles.
(2) Despite subsection (1), a driver of a vehicle must not cause the vehicle to overtake and pass another vehicle on the right
(a) when the movement cannot be made safely, or
(b) by driving the vehicle off the roadway.

Reference:

Lane changing tips – BC Driving Blog

Turns signals category – BC Driving Blog

Passing on the right – DriveSmartBC

Passing on the right collision liability – DriveSmartBC