Thanks for the quick reply.
The thing is, it's supposed to be a voting system for surf/skimboard competitions (and later for any kind of sports), so it will have to be a system that can be carried to the beach. If i have to set a wireless router at the beach that can be a headache.
As for security, i'm not really worried, at least for now, since i suppose that the beach is not a place where you find threats

The stability is an issue though, because the votes have to be cast pretty fast while the surfers are in their time limited rounds, and nothing can fail at that moment.
What about BlueTooth? Shares the same stability problems as an ad hoc WI-fi?