Immigration USA, problems with ESTA

Filling out ESTA, for the immigration to the USA, Problems occur when trying to differenciate´Zero´and ´O. Latterly airline personnel is checking the ESTA application extremely accurate during the check-in procedere.
Guests of our Villa BelAir had problems at Düsseldorf airport when trying to check-in, because it is not easy to differenciate ´zero´ and ´O´ in the new european passports and our guests made mistakes. Fortunately the problem could be solved, because Düsseldorf airport offers computer terminals with internet access, and they could correct their ESTA application directly on site. But we strongly recommend, to check your application carefully at home, considering the ´zero´and ´O´ problem. If neccessary you can correct the mistake without any stress and pressure of time. We also suggest to print the ESTA application confirmation and also the flight confirmation of your flights to an from Florida, because you will be asked for these at the check-in counter.