Do you tell your coworker when their fly is down

"Yo, bro, wardrobe malfunction!" Little smile and nod at crotch.

Unless it's a dickhead boss, in which case you say nothing whatsoever.

Depends if they are packing something worth a sneak peak. If so, enjoy the view and leave it to someone else to acknowledge.

There's no winning, because if you're a woman, that coworker will think you're dtf if you're not friends with them.

What you have to do is sell it in your delivery of the statement. For me, if it's a coworker I'm friends with I would turn it into a joke (much like in Boojum's post) and go, "Man, do you not know how pants work, or is this some weird fetish?" He'll look at me like I'm crazy, I'll just let him know his fly is down, he'll laugh and fix it.

If it's a coworker you don't know well, then pretend like you're doing him a favor by telling him. For example, "Jimmy, I just noticed your fly is down. Please fix that before the girls see." If you don't have female coworkers, substitute "girls" with "boss" or something.

Boojum nailed it.
If it's a friend you point things out:
There's a booger hanging.
I can see your nip.
You're unzipped.
I can smell weed on you,
Etc.
If it's not a friend.
Not your problem.

If you want to add a little humor, "Hey Old MacDonald, the barn door is open, EIEIO."

I've never seen this, though I have seen a lot of ass - and in those cases I don't bother to tell them to put their pants up.

I guess it depends how you do it. Delivery bro 👌

Yeah, I'd tell them. I'd expect them to tell me too. Nothing remotely weird about it.

Yes, definitely. I had a former manager, who was a nice guy, kind of quiet, and a big guy. We liked him, but, would often come back from the men's room with his zipper down. Our office was mostly women, with myself and him as the only guys (other than a consultant who came in once in a while). The main secretary would hint at it, but it was usually on me to intone or somehow let him know..Mark, pull up. He was the manager and couldn't be walking around the office with his zipper down..

What does "deoends" mean?