I'm not sure if anyone here uses Butler, but it has a cool feature that lets you trigger an "event" (read "macro") when you mouseover or click a hot-corner.
I think this would be an incredibly useful feature for Keyboard Maestro. Mouse over Hot Corner bottom-left > type iCloud password. 
Source: Butler Help
It is on the todo list
Fantastic! Looking forward to the update. 
+1. Came here to request the same.
with and without modifier keys if possible please, =)
At the moment, and for lack of anything better, I'm using BetterTouchTool and its ability to receive AppleScripts for each of these 4 corners. Associated with a key (Option, Command, Control or Shift), one then has many possibilities to launch actions ...
Integrating Hot Corner in Keyboard Maestro would be a very nice comfort ...?
Why wait... 
You can use the gestures action in KM and have more than 4 corners to choose from.
Another advantage is that you don't have to move the cursor across the desktop.
Okay to have more than 4 configurations that the 4 corners available, but I find it very effective not to have to "draw" and / or click with the mouse. With the solution offered by BetterTouchTool, you just have to move the mouse pointer quickly to the corners, regardless of the foreground application and some windows below.
Not at this time.
Surprised this hasn't been implemented.
BetterTouchTool is my fav for hot corner tirggers. 
that this is added to KM, as rn I'm running 4+ automation apps, always on in the background, my computer would probably be happier if just KM was running :).
Has this been implemented by any chance? I mean "Slide to screen edge" and "Hot corners" triggers?
where in BTT to go:
(replying here as I was googleing BTT hot corners and Google lead me back to my own post: proof of concept, so I knew it was possible. After refigureing it out, posting a reply here to help others or myself in the years future 
.) Perhaps hot corner triggers will be added to KM one day:crossed_fingers:.
