El Ciego,
Yes, they should provide something for you. That might mean a hotel, food voucher, free phone card, free ticket, transportation to/from the hotel, shaving kit, etc.
As you already know, flying with disabilities puts anyone at a big disadvantage. Of course they should provide someone to help you but there are never any guarantees. I'm sure you always make sure the airline makes note on your reservation that you are without sight. Hopefully someone actually reads it.
"Rule 240" is the airline slang for the code that is supposed to cover what the airline will do for you in case of a break in service. The FAA says they must provide certain things if a domestic flight is delayed more than 2 hours. An international flight 4 hours. Basically all they are required to provide is transportation. What they WILL provide might be more depending on how you ask and what mood the agent your are dealing with is in at that moment. The airlines all have their own guidelines and leave quite a lot up to the discretion of the gate personnel.
Yes, you do have rights. You also have a "contract of carriage" with the airline. The key is to know what they are and handle it with courtesy. The people working the gates don't want a bunch of pissed-off customers anymore than any passenger wants to be delayed.
Work with them and they'll work with you. They have a number of things they can do for you but be polite. There are probably many others in just as dire straits as you (or worse) and EVERYONE wants to get where they were going.
One key element to remember is whenever possible DO NOT WAIT IN LINE to get another flight. Call the airline's 800 number. That person has the same access to flights as the ticket counter person who has to work them one at a time.
They will usually only cover problems NOT defined as "FORCE MAJEURE EVENT" (acts of God, weather related, war, etc). Keep in mind a rain storm in one city (like Atlanta) can have disasterous effects on planes getting into or out of another city.
I've seen people bitch and yell at gate personnel in one city because the plane is on a weather hold in another city: "THE SUN IS SHINING!"
Since they are cutting back on planes and personal to fly them there might be a big gap in providing out of schedule service.
Delays are one of the reasons I always fly with some MONEY in my pocket, a bottle of water, some granola bars or such snacks, a list of phone numbers and a magazine, book and/or DVD player/iPOD, etc to keep myself amused. Don't forget your AC adapter.
Know your rights BEFORE you leave home. Pay attention to the section marked "DELAYED AND CANCELED FLIGHTS".
http://airconsumer.ost.dot.gov/publicat ... rights.htm
Rule 240
http://www.mytravelrights.com/travellaw.cfm?ai=3