Certain terms are red flags. The phrase "any time for any reason" means that the issuer can hike your rate at will even if you've never been late with your bill. And statements like "defaults to other creditors" or "delinquent on an account with any other creditors" mean that the card company practices universal default and can raise your rate if you make a late payment on any loan anywhere.
The Federal Reserve has put forth proposals that would eliminate these practices. In the meantime, however, you should call customer service before you apply to find out whether the card has these sneaky terms, advises Curtis Arnold, author of "How You Can Profit from Credit Cards" and founder of CardRatings.com.