There are aura readers, fortunetellers, and palm readers. Every psychic I know has his or her own unique way of using his or her abilities. It just isn't so. Yes, some psychics are less ethical than others are, but most professionals turn off their abilities when they're in public. In fact, every hard-working psychic I know will tell you that at the end of a long day of reading people, the last thing he or she wants to do is read people's minds.
Most professional psychics work that way in order to prevent burnout.
It is usually very easy to tell if people are in the early stages of their psychic development. If they've been around awhile, they're respectful of people's boundaries and don't read them unless asked. But those in the beginning stages often get excited and want to show people what they can do, and it can cause problems when they don't wait for people to ask. If you're ever in a situation like the women at the baby shower, and are uncomfortable in any way because you don't know if a psychic is respecting your boundaries, just ask God to put protection around you, so that no one can read you unless you ask. This is usually not necessary, however, with professional psychics who have been around awhile.