Also, wouldn't no-shows and on-board upgrades not necessarily involve communications since they are only known on-board anyway.
Also, I don't think Upstate is suggesting Amtrak not sell tickets further down the line, only not use e-tickets if the data could not be manually downloaded before the passenger boards.
The conductor's device would have to be programmed to allow the him to enter paper tickets, upgrades, and no shows, plus who knows what other type of information.
Right now under the current system no shows are only known on board, but upgrades are known both onboard and to anyone with access to ARROW. Or perhaps more correctly, anyone with access to ARROW will not be able to sell a sleeper that was sold via an onboard upgrade. Additionally, no shows are only known if they happen in the sleepers, not coach.
However the point of the system, and in fact it was the point of the system that Amtrak tried to develop for Acela, is to be able to sell the seats/sleepers of no shows further down the line. If the conductor is unable to upload that info, then a no show's seat cannot be resold and potential revenue could be lost.
As for selling regular tickets vs e-tickets, unless Amtrak is going to go to additional lengths beyond what other similar systems use, a conductor will scan all tickets with his scanner. That means both regular current style tickets and e-tickets. If the conductors device is unable to download info as the train moves along, then the device will reject a regular "typical" ticket when he scans that barcode since it won't be considered valid without a download to update his hand held device.
So the bottom line is that it won't matter if you have a regular ticket or an e-ticket, if the conductor's device is off line, then it will reject either type of ticket as being invalid.