Etickets are a huge convenience to those of us who don't live near a station. We've always booked far in advance and had time for our paper tickets to be mailed to us, but on short notice the etickets would save the day. And they can't be lost, which is another great advantage.
However, I too am very concerned about having the rest of a trip cancelled if the conductors don't do their jobs correctly! When your long distance accommodations are gone and there are no more to be had, there's no way for the error to be fixed. Even in the best case scenario, it would be an inconvenience and be temporarily stressful. I consider this a major problem that needs to be very high priority on the list of things to fix.
Many people don't appreciate being reminded to do their job correctly, even when done in the most polite, respectful way. I'm not helpless and don't mind tending to some things which aren't my responsibility (that is life and no big deal), but I don't want the burden of having to basically tell a conductor what to do. Awkward!
Amtrak is very good about many things, but they seem to choose some strange things to let slide by. Seems someone needs to prioritize the to-do list. (OT but--Another thing that would rank high is having agents understand the basic rules and how the system works re what is an allowed accommodation change, AGR redemption, etc.. That couldn't be that hard to learn, and isn't an unreasonable job requirement, when it is your full-time job. Those who frequent this forum quickly learn rules that you apparently have only about a 50/50 chance of getting an agent who knows the same things.)
This is just strange to me!