otherwise XPOI will unfortunately be not very useful, as, when you need it, it is likely not to work.
It's not "likely" to have it not working, it only happened a couple of times in the about 2 years XPOI has been released. According to the genonames admins, the overload was caused by smartphone applications that connects there, due to the high phone sales in the holidays period.
Isn't it possible to use an offline database, that would be used when the geonames servers aren't available. That database would obviously not be always up to date, but I think that's not such a problem !
It wouldn't be trivial to support an offline database, but we are looking into a different solution. Geonames also offers a premium access option with an higher availability, we need to evaluate the traffic generation potential against the cost and the number of users.