I'm glad to know that most people out there do know the reality- we shouldn't be overusing antibiotics anymore- they aren't a 'miracle' and resistance is developing.
if you take it,and give at the first sign of trouble, I have to assume you'd do it no matter where you were if child got sick- and any doctor who precribes without a culture needs to be updated on the new research which proves that a HUGE % of ear infections clear by themselves in the same span of time that the group taking the meds for it....
Antibiotics are not pain relievers either! tylenol(in careful doses) is-
If my kid had chronic problems-I'd speak to my doc beforehand, and be able to have him call a prescrip into the nearest pharmacy if needed- but this again is a flawed science, giving this stuff without clear proof that it's necessary is dangerous. just a stop gap measure, used once for vacation would be ok- but never preventatively-
I don't know the exact science on how these work, but 'bacteria' in the body somewhere? Our bodies are full of different bacterias at all times, some good, some not. broad spectrum anitbiotics desrtroy all bacteria, good,bad and ugly! This can result in terrible health consequences.
Healthy foods, taking airborne once a day, nutritious vitamins if you want(no junk food vitamins

) religious hand washing, sending wipes in their lunchboxes to school,keeping Purell in their backpacks and in the car... there isn't any guarantee anyway- I've been taking the kid to WDW for 13 years now, and somebody usually gets some complaint...no biggie, it's just life!
As far as knowing WHY ear infections occur, another suggestion could be allergies of some sort- many people have hidden sensitivities to food,airborne substances they never even imagined!