This is more like a comment that could be expanded on. I overheard someone talk about the fact that they’ve received an email from someone that said they were cousins through DNA. The person was not an Ancestry subscriber, so they were asking if they could somehow get into Ancestry and actually see if the person was on their matches list to check that it wasn’t spam or phishing. As I am an Ancestry subscriber, I haven’t given a thought to what non-members can see or not. If I want to correspond, I’ll do an initial note through Ancestry, but will also give my personal email to correspond outside Ancestry. (FamilyTreeDNA lets you email them directly.)
It might be a good idea to talk about how to be careful when replying, and also the information to give when requesting someone else’s information. For instance, I had someone contact me saying “Ancestry says we’re 100% related!” (That’s a quote, by the way!) and going on about being being given up for adoption in Texas. Since I knew she wasn’t actually me, I did some digging and found out we were about 4th cousins, so I replied and gave her some info about what that meant and talked about lines (by location) that might be fruitful to explore. This would not have been the first time that I found out I had siblings I didn’t know about (and from Texas, no less), so her initial note had an effect she probably didn’t intend. It is important to approach people thoughtfully and understand what you’re asking. So, comments on safety and comments on how to contact possible cousins would be a good thing for beginning DNA-ers to know.