Last May, I was attempting to return to the states from Milan and United canceled the flight (it had actually never left IAD the prior evening). I had always used ETickets for my domestic travel and didn't see any reason not to do so internationally. That was a BIG MISTAKE, further exacerbated by United's inept handling of the entire re-accommodation process in MXP!

I guess, in retrospect, I really should have known better. Although I had used ETickets to LHR for several trips last year, the concept really seemed to confuse the check-in agents and it tuned out to be much more hassle than it was worth.

After waiting in line for several hours at MXP to be reprocessed, I was eventually told that they could not help me, I had an ETicket and needed to wait on a different line elsewhere in the terminal to get a paper ticket issued. Why couldn't they have had an agent working the line and pointing people in the right direction?

Once I arrived at the END of other line, I needed to wait several more hours until it was my turn once again. It was bedlam. Nearly an entire 777s worth of people waiting to be serviced, many of them not even knowing what an ETicket was, let alone whether or not they actually owned one. I actually wound up walking through the line, pointing people in the right direction and offering scheduling advice.

When it was my turn to approach the counter, it was now well into the afternoon and there were no more flight options left, even on other carriers. It wound up taking me an extra two days to return from Italy. Ironically, once I was re-accommodated on another flight, they insisted on issuing me an ETicket, again!

So, I must echo all of the advice you have received thus far. You should most definitely get your ETicket converted to a paper ticket. The fact that it is a free ticket, does not necessarily mean that you will not be transferred to another airline should a problem arise. United has done it for me in the past, well before I started travelling very frequently.