magnet in watch band causing laptop to sleep

This isn't a question, just an interesting observation that might help someone out.

When the magnet on my Milanese Loop band gets near the 'fn' key on my laptop (MacBook Pro 13-inch, Mid 2012), the screen briefly goes dark because the computer thinks the lid is being shut. As soon as I move away, it brightens back up.

It really made me wonder when I was typing away today, and took a few minutes of experimentation to figure out what was happening. I was glad it wasn't a real hardware issue, but you can see how I worried there for a minute.

Just thought I would throw it out there in case anyone else has this happen.