I was on an Easyjet flight back from Rome yesterday and they announced that from 30th April they would only allow online check-in. The desks at the airport will only be for bag drop off. Given the nature of the announcement I don't know if you'll even be able to use machines at the airport to check in. This was the first I have heard of this.
For many it will not be an issue and I expect that for any reservations made now this will be made very clear at the time of booking. There are bound to be some however who get caught out by this.
You have been warned!