Let’s answer the question with a question: is swimming in the ocean safe? Sure it is, until you come across a shark that has not eaten in a couple days and thinks you look a lot like a buffet in a brightly colored swimsuit.
Much like the ocean there is a constant threat that surrounds you. However, unlike the ocean, this threat is more widespread. While your chances of being attacked by a hungry shark are one in a million, your chances of being attacked on public Wi-Fi are much, much greater. Once you place yourself on a public network connection, you are truly opening yourself up to the potential for infections and compromise, as anyone else with a wireless-capable device can potentially “see” you. Am I therefore saying NOT to use publically available access, such as in restaurants, airports, and coffee shops? No. Going back to our ocean example, you would not avoid the ocean all together because of the potential dangers, but you also would not jump in wearing a seal-shaped suit while covered in fish bait in the middle of a feeding frenzy. (OK, maybe one or two of you would, but…)
It would be in your best interest to be AWARE of the dangers and take a few precautions:
I only utilize public Wi-Fi sessions, personally, for random web surfing, such as for directions, reading reviews, or checking movie times. I prefer to only enter my information (passwords, etc.) when I am on networks I “know” and can “trust” with relative certainty, such as at my home or office.
(FYI: This article is reprinted from my book, "Don't Throw IT, Get to Know IT (A Computer Guide for the Technically Challenged)" available as an eBook on Amazon - Wiltz Cutrer)