This came up in discussion a while back. What happens if you have a highly populated area of google map api points, and they are all clickable on? Its likely that you wont be able to get at them all.

http://groups.google.com/group/Google-Maps-API/browse_thread/thread/f1e1d5bb5b913535 – this link (and links from it) provide useful insight into it.

Image Credit: tamakisono