To get this back to the OP, I think accelerators being sort of a 3-month extreme reality-show experiment where they need you to fly into the valley and then lock you in a room and throw away the key is just not something older people with family obligations can pull off--not if they value their families.
I disagree with Glenn. I went in to TechStars from 9 to 5 except for the Wednesday night additional meetings. I saw my kids the same as anyone working a "normal" job. That said, during TS I defiitely pulled the laptop back out after the kids went to bed! It was a tough 3 months, but it is 100% doable with a family. If you have a spouse that believes in you and what you're doing, this helps make the time go faster.
As a single father not living in California anymore, I couldn't pull it off without major family disruption. I also think the pressure of achieving a major milestone in such a short timeframe would make it very hard to stick to a 9-5 schedule, regardless of official expectations. I'm not convinced running the gauntlet like that is necessarily what all startups should aspire to do. There's no one-size-fits-all.