canon - Why doesn't focus confirmation appear in AI-servo mode?

Camera: Canon 700D

Lens: EF-S 55-250mm STM

So far I have been shooting still subjects. But recently I wanted to photograph moving people (skaters).

I changed the AF mode to AI-Servo (as skaters are obviously moving all the time) and started taking photos.

To my surprise, the green focus confirmation dot that normally appears at the bottom right of the viewfinder did not fire up at all! I read the camera manual and this is a known feature. The focus confirmation light indeed does not work in AI-Servo mode.

I am a bit puzzled now. How am I supposed to know if my shot is in focus? Am I supposed to "spray and pray" that I get good shots?

Or there is some other camera setting that I am not aware of?

Update: By "focus confirmation dot" I am not talking about the red focus points. I am talking about the green confirmation dot that appears at the bottom right of the viewfinder that says to me "focus has been achieved".

Answer

The reason the focus confirmation light does not function in AI Servo mode is because the camera never stops tracking the subject and adjusting focus as necessary. The green focus confirmation light in the lower right corner of the viewfinder is an indicator that AF has been locked and has stopped measuring focus. That's the last thing you want to happen in AI Servo mode! With a moving target the green light wouldn't guarantee your subject is in focus, it would only confirm your subject was in focus at the distance it was from you when the AF was locked.

With the appropriate menu selections with some (but not all) Canon models the viewfinder can be set up so that when doing tracking of moving subjects the focus points currently in focus are the only ones appearing on the LCD overlay visible in the viewfinder. Models that have such capability include the 1D X, 1D X Mark II, and 7D Mark II. The 700D, as a more budget oriented model, does not feature an RGB+ir light meter and the processing power needed to run Canon's iTR (Intelligent Tracking and Recognition) AF in concert with the PDAF sensor.

Since your camera lacks the capability of the iTR AF, your best option is to do it the old fashioned way: use your eye pressed to the viewfinder to confirm your subject is in focus. Do note that if the camera can't focus on something it will warn you by rapidly flashing the green AF confirmation light. The more you practice it the better you will get at seeing what the AF system is really targeting and seeing when your subject is the center of focus.