FlyerTalk Evangelist
Join Date: Dec 2002
Location: Danville, CA, USA;
Programs: UA 1MM, WN CP, Marriott LT Plat, Hilton Gold, IC Plat
Posts: 15,721
The only reason to have a paper ticket is if you think you might need to take it to another carrier in the event of service interruption.
For example, when a strike occurs, other carriers will often try to accomodate passengers on a space available basis and accept the original ticket as payment (which they later submit to the original carrier for collection). If you have an e-ticket, that usually won't work.
With respect to a possible US shutdown, I don't think it will matter whether you have e-tix or paper for award travel. UA and other *A carriers will still have a record of your e-ticket in their reservation systems. Whether they choose to honor that ticket is a matter of some debate.
IMO it is highly unlikely that a non-*A carrier will honor a US award ticket for travel - they aren't in the business of providing free travel to competitor's customers.