Summarize:

There are some cases when winking can cause socially awkward situations or even get you in trouble. Be careful, in particular, about winking at the opposite sex.  Winking at someone of the opposite sex is often assumed to be an act of flirting. If this isn't your intention, think twice about winking. You may be misunderstood, especially if the person you are winking at doesn't know you well. A misplaced wink can make people angry, especially if it might convey that you aren't taking them seriously or that you are being inappropriately sexual. Especially if you are in a position of authority, be careful about the situations you wink in.
Know when not to wink.