Exactly. When you are taking someone in their 80s that uses and ECV, the monorail is a huge feature we depend on. Why they don't close it and work at NIGHT when the park is closed is beyond me. Why do it when people are using it during the day. If it were that much of a safety issue they wouldn't run it at all, not just close it during the day.
It's not a safety issue in terms of guest safety. As the previous poster said, the construction of the DVC Villas at the Grand Floridian is interrupting the monorail. If it's a safety issue, it's in terms of worker safety as they complete VGF.
As for why they are closing during the day instead of at night, there are two options:
1) Maybe they are working on it at night too.
2) If they're not working on it at night, perhaps there are reasons that the construction can't be done at night. Again, they're doing major construction. It's possible that whatever they're doing would interrupt GF guests throughout the night, and closing the monorail for limited hours may be the lesser of two evils compared to the sound of jackhammers keeping GF guests awake at night.
It does stink for those people who wanted to use the monorail, but Disney wouldn't close it unless it was a necessity.
In general, I agree with all those posters who said that Disney should have given guests more notice. However, I can't think of anything that affected guests could choose to do instead - monorails don't serve any other resort areas, so it's not like switching to a different hotel would make any difference.
Construction of VGF interrupted the WDW monorail on several other occasions earlier in the project too:
http://articles.orlandosentinel.com/2011-07-11/the-daily-disney/os-disney-world-monorail-hours-20110711_1_monorail-trains-monorail-fleet-zoraya-suarez
It sounds like they followed a similar plan back then: announcing construction only a week or so before it happened, and then closing it for limited hours during the middle of the day.
When I saw the Grand Floridian DVC construction begin, I wondered whether it might affect monorail operation, but it looked to be far enough from the rail. The GF DVC doesn't have its own stop, so there's no inherent reason to think that it should have done so. However, we have known for months that the GF DVC would open in October 2013 - just weeks away. So, for those of you who absolutely need the monorail, you might want to plan your visits in future years to avoid the completion date of the Polynesian DVC, just in case!
On the other hand, it sounds like the Polynesian resort itself may require more extensive renovation. If they have to essentially rebuild the Grand Ceremonial House, you can bet that the monorail will be impacted. I would recommend following Tikiman's various news sites.
Monorail interruptions aren't new to Disney. The
Disneyland monorail is more of a ride than a transportation feature, but it closed for an extensive amount of time from 1999-2001 as California Adventure and the Grand Californian were built. It could be worse...