Recently flew Alitalia from JFK to Rome. I went online to the Alitalia site and obtained boarding passes.

When we got to JFK, the passes were not accepted at the security checkpoint, we were told we had to go to the Alitalia counter to obtain boarding passes there.

We went to the counter, were given new boarding passes, and were told that indeed the online passes were not acceptable.

Any idea why Alitalia issues online boarding passes for JFK if they are not accepted at the airport?