Hey, thanks very much for all the replies. Haven't had a chance to monitor this thread as closely as I would have liked and to respond to all your comments.
I agree, from my own experience rpg gaming can get fairly loud and boisterous, and has at times included mock sword fights, dancing, and funny voices. Perhaps, if games are played at libraries, it is best to have a private room to play in. At the same time, the noise could be a positive thing as well. It shows that the library is open to having fun, and if people are coming over to watch you play, you never know they might be potential new players.
The main problem I've always run into with playing rpgs in cafes and the like are that there is never enough room for everything, and heaven forbid you knock your drink onto someone's character sheet!