I know a guy who was having his gelousie glass removed. He shined the WML from his AR at the guy. The guy was blinded but continued to remove the glass. So he pointed the rifle toward the ceiling which illuminated the rifle. The bad guy saw the rifle and ran off. So the light saved him from having to use his rifle. I bought a WML shortly after I was told this story.
If I'm armed and have the element of surprise, I'd rather make sure this burglar is caught, not just scared off. I know this is Monday morning quarterbacking, but I've considered these scenarios already. If I have the upper hand, I'm less likely to give the guy an invitation to leave.
There's nothing legally that requires you to warn someone breaking into your house that you're armed. You can call 911, stand beside the window out of sight, and not announce your presence until he's inside.
Warning them leaves them free to victimize others -- or even yourself on another night/day.
If the dispatcher knows I have the guy detained at gunpoint, hopefully that will expedite the Cops' arrival.
This plan would change if I see he's got a buddy with him. Being outnumbered is a bigger risk than detaining one perp.