If they are jeapordizing health and safety and had reasonable alternatives (go to provisional airport and deal with the situation rather than hold for 2hrs with hope that wx might improve at the regular), then yes. There would probably need to be some other factors, but bottom line is that keeping people locked up in an airplane on the ground for hours on end is wrong. If this happens, the airlines should be prepared to deal with it, and not by just keeping them locked up. If they are not, then they are over-extended in terms of their abilities, infrastructure and service to the public, and they should not be offering so many flights in the first place. Maybe after a few of them go out of business then there won't be so much traffic? If you're going to complain that it's the FAA that needs to make more capacity, then please tell me how much you're donating to the cause.

To say that "we can't control the FAA, traffic, or weather" is a cop-out. Everyone knows you can't control those things, but if you are offering a service you better have the means to back it up when things do go wrong, rather than just saying "oh well, there's nothing we can do".

There are obvious health and safety issues with keeping people on a plane on the ground.