Absolutely. It varies by state. In most states most private businesses can't prohibit concealed carry; in other states they can, but only with specific language on a certain size sign. Plus, if you violate, it's just "please leave". There are legal prohibitions against carry in certain places under state law (usually bars, schools, sometimes government buildings), and there are federal prohibitions at airports. Not carrying when you're going to be drinking, or at a place like a club where people will be bumping up against you, is probably a good and prudent idea.
If it is concealed, no one should know. Open carry IMO is a bad idea in a lot of places, and not something I would want to encourage. That is what Starbucks seems to have a problem with. Open carry is bad because it makes weapon retention a much bigger problem, plus it negates the "no one knows who MIGHT be armed" value of citizen concealed carry. Also, if I were doing open carry, I would feel obligated to carry something like a $3500 Les Baer 1911 or a Colt Python, vs. a $500 Glock.
If it is concealed, no one should know. Open carry IMO is a bad idea in a lot of places, and not something I would want to encourage. That is what Starbucks seems to have a problem with. Open carry is bad because it makes weapon retention a much bigger problem, plus it negates the "no one knows who MIGHT be armed" value of citizen concealed carry. Also, if I were doing open carry, I would feel obligated to carry something like a $3500 Les Baer 1911 or a Colt Python, vs. a $500 Glock.