How do you ensure one of your app's hotkeys isn't reserved?

I was just stymied by a bug report of a hotkey not working in my app that I couldn't reproduce.

It turned out that Mission Control hijacks Ctrl-arrow hotkeys, but I have all that turned off on my system.

How do you check a hotkey you're planning to use in your app against ones in use by the OS? A Web search on this issue turns up plenty of questions but no answers that I've seen.

Another annoyance is that the menu bar showed that the hotkey was going to work.
How do you ensure one of your app's hotkeys isn't reserved?
 
 
Q