Supper common question: Why are you learning the language?
If it is a high turnover group it is kind of boring to answer the question every single time. You may use the wiki to list your reasons on your User Page... and you may wish to have a short canned answer.
At least one meetup group has been divided by some people acting inappropriately. Most of these are public events, but some people have felt the need to make exclusive clubs to feel safer. Don't be a creep.
Purchase stuff from the host business. Tip well.