No. They dun do that. Once full. No more new subscription to unifi until they add ports. Each pole or each green box serves certain cluster of houses within the same street. Even there are free ports at the same street from other pole or other green box, they dun pull cable from other pole or box that does not belong to yr house cluster to install for u.

last time I installed my parent house time left two ports. After installed few months now, check address again no more port, even my parent house Neighbour unit also no port, because they shared the same pole.

Alternatively, actually what u can do is to subscribe to maxis. Unifi no port, does not mean maxis no too.
Because somehow they seems to have reserved port for maxis.