Has anyone ever specified Polished Concrete for Exterior

I have a client who wants us to specify diamond polished concrete for exterior balconies on a condominium project.

Scary.
Any comments from the peanut gallery?

I’m working with RetroPlate right now for an interior polished concrete; I don’t consider myself anywhere near knowledgeable, so I’d be asking someone who does this. I got the following two companies from my RetroPlate rep here in WI for a project in Florida:

A. Konchan Polishing; 4530 S. Florida Ave., Inverness, FL, Matt Konchan, 362-341-1017.
B. Ardor Solutions, 1718 Kennedy Point TE1016, Oviedo, FL, Stan Tucker, 407-672-0023.