I did it. I wanted a pricy stroller, but couldn't afford new so found it used. (Ironically I then discovered babywearing and rarely even use it now!
BUT I would check a few things:
- do the brakes work? Not that I'd ever trust them implicitly, but if anything is a safety issue on a stroller I'd say it's this,
- watch for potential pinch-points. A wise recommendation on pretty much all strollers, but I imagine some would be better than others, and
- are there any broken/sharp parts that could be dangerous. Kind of goes without saying.
Oh, and I'd check for rust but I wouldn't say that's a safety issue, rather a value issue.