True, in such a case it's better to be safe than sorry. What are you going to mis, the chance to talk to someone? Small loss for not freaking someone out.
perhaps miss the chance of meeting the love of your life and the future mother of your children, or maybe just a great friend with whom you'll have hundreds of interesting conversations, and who will help you through the hard moments of your life, versus being quickly dismissed, and described as creepy by someone who doesn't want to know you to a bunch of people you will probably never meet.
Eh, i chat up elderly people on bus stops, often compliment nice jackets or boots of complete strangers, and used to approach attractive people with no problems. I don't think i've ever come across as creepy... maybe that one time when it was somewhat reasonably late and i asked a lone guy for directions; he was significantly taller than i am, but seemed somewhat nervous.
Once, circa 10 years ago on a trip to Scotland, i saw a guy reading Terry Pratchett's Jingo. I had recently discovered the author, it's somewhat unknown in my country, and i was pleasantly surprised by finding another reader of Pratchett's work, so i chatted this guy a bit. He was re-reading the book and happily gave it away, it was my first untranslated Pratchett, and i never read a translated book of his again. I later discovered Pratchett was the best selling author in the UK at the time, so that wasn't that big of a coincidence.
On the other hand, i tried and failed spectacularly to work as a telemarketer, so i guess i have an innate sense of opportunity.