Depends on the situation! I had a coworker at a former job and I noticed he stuttered when he gave his little intro speech during a meeting when he was first hired so I sent him an email later, like “hey welcome to the team! I hope I’m not off-base here but I recognized some of your speech patterns and wonder if you stutter? I do too!” We never really talked about it again, but he seemed to appreciate that I reached out in kinship. If I met a PWS in passing I probably wouldn’t mention it unless we were having a deep interaction, feels easier to just mind my business and let them go on with their day. But at the same time I wouldn’t mind if the roles were reversed, so idk.